CN102707437A - Light pulse shaper based on double-array fiber grating and working method thereof - Google Patents

Abstract

An optical pulse shaper based on a double-array fiber grating, which consists of an optical frequency comb source, an optical isolator and an amplitude controller. The output end of the optical frequency comb source is connected to the input end of the optical isolator, and the output end of the optical isolator is connected to the The input end of the amplitude controller, and the output end of the amplitude controller output even-function waveform optical pulses; a working method of the above-mentioned optical pulse shaper based on the dual-array fiber grating: (1) input, (2) amplitude control: including light splitting , Phase adjustment, interference, (3) output. The advantages of the present invention: 1. The spectral amplitude can be continuously and precisely changed by only using the optical fiber stretcher to realize the dynamic adjustment of the spectral amplitude; 2. The structure is simple, the loss is small, and it is easy to couple with other optical devices; 3. It can output arbitrary waveform light pulses with even function waveforms; 4. The shaping bandwidth can be increased by increasing the wavelength interval between adjacent gratings or increasing the number of gratings, so that the bandwidth of the device can be easily upgraded.

Description

Optical pulse shaper based on double array fiber grating and its working method

(1) Technical field:

The invention relates to an ultra-short optical pulse shaper and its working method, in particular to a line-by-line shaping of an input light pulse in the frequency domain by using the phase control and interference effect of a double-array fiber Bragg grating to control the amplitude of each spectral line , an optical pulse shaper for realizing arbitrary even function waveform and its working method.

(two) background technology:

In the past two decades, due to the development of ultrashort optical pulse technology and the widespread use of femtosecond laser systems, and many applications require ultrafast optical pulses, optical pulses of arbitrary shape, pulse shaping systems have achieved rapid It has a great impact on ultrafast laser spectroscopy, nonlinear fiber optics, high energy physics and other fields. Arbitrary waveform optical pulse generation (O-AWG) technology has many applications in the field of optical fiber communication, such as (1) generating ultra-short pulses with ultra-high repetition rates as pulse sources, optical clocks, etc.; Perform transformation to generate a code pattern suitable for optical communication and improve communication performance; (3) Reshape the optical signal at the receiving end of the ultra-high-speed communication system to improve signal quality and bit error rate.

Optical pulse shaping methods can be divided into direct time-domain shaping and direct frequency-domain shaping. For ultra-short optical pulse shaping, if time-domain shaping is used, a high sampling rate is required, so frequency-domain shaping is generally used, where The widely used and developed frequency domain shaping method is based on the principle of Fourier transform. By changing the amplitude and phase of each spectral component of the filter function in the frequency domain, the spectrum of the output signal is changed to obtain the desired waveform. In the past, spectrum shaping operated on a set of spectral lines instead of each spectral line, and the resulting time-domain waveform had a very low duty cycle. Due to the development of optical passive devices, such as fiber gratings, arrayed waveguide gratings, and diffraction gratings, they can be conveniently used for spectrum separation, making it possible to independently manipulate the amplitude and phase of each spectral line. The traditional arbitrary waveform optical pulse generation system uses a liquid crystal spatial light modulator combined with a diffraction grating as a dispersion device in structure, which has disadvantages such as complex collimation control, bulky size, and high coupling loss. Arrayed waveguide gratings have a large number of channels and can filter multiple wavelengths at the same time, but the high resolution increases the physical area occupied by it, making it difficult to control the uniformity inside the device. The shaping system using fiber gratings to separate the spectrum has a series of advantages such as small size, low loss, good stability, and easy integration. In 1983, Froehly first proposed a 4f zero-dispersion system with a pair of diffraction gratings and prisms and a fixed mask to shape picosecond pulses. However, since the spatial mask is binary in both amplitude and phase modulation, it cannot adapt to The change of the input pulse belongs to the static progressive shaping, and it cannot produce a real arbitrary waveform optical pulse. In 1995, A.W. Weiner and others proposed to use liquid crystal spatial light modulator (LCSLM) to shape femtosecond pulses, which overcomes the above-mentioned shortcomings and realizes continuous modulation of amplitude and phase. At present, liquid crystal spatial light modulators and diffraction gratings have been used. The structure has shaped the 108 spectral lines with a spectral line interval of 5GHZ, and output a waveform with complex shapes; the 15 spectral lines with a spectral line interval of 10GHz have been adjusted by using a 64-channel arrayed waveguide The spectral line is shaped to obtain a transformation-limited pulse with a super-Gaussian spectral amplitude and a spectral phase of 0, and implement different phase controls to obtain a pulse with a changed pulse width and shape in the time domain; a 128-channel arrayed waveguide grating is used to pair Spectrum shaping with a spectral line spacing of 40GHz, and a shaping bandwidth of up to 5.1THz. At the same time, people have made a series of efforts in dynamic pulse shaping. Dynamic spectrum shaping requires that the spectral response of the shaper can adapt to the changes of the input waveform and the target waveform, and the spectral line spacing and bandwidth must be adjustable at the same time. For example, in 2008, Yu Yeung (Kenny) Ho used cascaded fiber gratings and fiber stretchers to control the phase, polarization controllers and polarizers to control the amplitude, and shaped a few spectral lines to obtain approximate sawtooth Pulse and rectangular pulse waveforms.

At present, the devices used for amplitude shaping mainly include: (1) Electro-optic intensity modulators. Electro-optic modulation is based on the linear electro-optic effect of crystals, that is, the refractive index n of electro-optic materials changes with the applied external electric field E. The electro-optic modulator is an integrated optical device, and the most commonly used structure is a Mach-Zehnder interferometric modulator composed of a titanium diffusion waveguide on the surface of a LiNbO ₃ crystal. Since there is a strict correspondence between the voltage applied to the modulator and the output light intensity, by properly selecting the working voltage applied to the modulator, it can be made that when an electric pulse of a certain shape is applied to the modulator, The output is a correspondingly shaped light pulse. (2) Adjustable attenuator, the current main technology is divided into: discrete micro-optical component technology, MEMS technology, optical waveguide technology. Among them, the discrete micro-optical component technology mainly uses mechanical methods, magneto-optic effects, thermo-optic effects, electro-optic effects, acousto-optic effects, etc. to change the size of the optical power. (3) The polarization controller is combined with the polarizer, and the polarization controller is used to convert the input arbitrary polarization state into a specified polarization state output, and the light intensity changes after different polarization states pass through the polarizer, and the polarizer is rotated once , the transmitted light intensity of circularly polarized light remains unchanged, while the transmitted light intensity of elliptically polarized light shows a continuous change from maximum value to minimum value maximum value to minimum value, but there is no extinction phenomenon, and the transmitted light intensity of linearly polarized light A continuous variation of maximum-extinction-maximum-extinction occurs. Control of the polarization state can thus be converted into intensity control.

The structure of the above intensity modulation method is relatively complicated, and it will increase the loss of the system and reduce the quality of shaping when used for spectrum progressive control, while the continuous all-fiber shaping system can obtain high-quality shaped light pulses on the basis of a simple structure. It can use the reflectivity of fiber grating to modulate the intensity of light. By controlling the reflectivity profile of uniform or inhomogeneous fiber Bragg gratings, such as linear chirped fiber Bragg gratings, sampling fiber Bragg gratings, superstructure fiber gratings, etc., to change the light intensity of different frequency components, at this time the fiber Bragg grating is used as a dispersion device Also as a shaping device, it can output light pulses whose spectral intensity is modulated. However, the reflectivity profile of the complex fiber grating requires a higher precision manufacturing process, and the manufactured shaper is not dynamic, and cannot change dynamically with the input waveform and the target waveform. Therefore, we propose a dual-array fiber Bragg The phase control of the grating and the structure of the interference effect realize dynamic optical pulse shaping.

(3) Contents of the invention:

The object of the present invention is to provide a kind of optical pulse shaper and working method thereof based on double-array fiber gratings, which utilizes the phase adjustment of the fiber stretcher and the interference effect of the double-array fiber grating to realize the control of the amplitude of each spectral line, Realize even function waveform optical pulse output.

The technical scheme of the present invention: an optical pulse shaper based on a dual-array fiber grating, characterized in that it consists of an optical frequency comb source, an optical isolator and an amplitude controller, and the output end of the optical frequency comb source is connected to the optical isolator The input terminal, the output terminal of the optical isolator is connected to the input terminal of the amplitude controller, and the output terminal of the amplitude controller outputs an even function waveform optical pulse; the said amplitude controller is composed of two fiber Bragg grating arrays and a coupler, and the coupler The port A of the coupler is connected to the output end of the optical isolator, the port B and port C of the coupler are respectively connected to two fiber Bragg grating arrays, and the port D of the coupler is the output end of the amplitude controller to output even function waveform light pulses; The fiber Bragg grating array is composed of at least two fiber Bragg gratings and at least one fiber stretcher arranged at intervals.

The central reflection wavelengths λ _n of the corresponding FBGs in the above-mentioned two FBG arrays are the same, and the difference between the central reflection wavelengths λ _n of two adjacent FBGs in each FBG array is the same.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in the source is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: The optical frequency comb source emits an optical frequency comb, and the optical frequency comb is input from port A of the coupler through an optical isolator;

(2) Amplitude control:

(2-1) Light splitting: the input optical frequency comb is divided into two signals by the coupler, and are input to two fiber Bragg grating arrays from port B and port C respectively;

和θ_n，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同。(2-2) Phase adjustment: select the spectral line equal to the central reflection wavelength λ _n by the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays, and adjust each fiber in the two fiber Bragg grating arrays at the same time. extender to realize the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating array, so that the phase shifts produced by the fiber Bragg grating array to each spectral line of the two signals are respectively

and θ _n , the profile of the magnitude spectrum of the two signals remains unchanged at this time, which is the same as that of the input optical frequency comb.

(2-3) Interference: The two signals reflected by the fiber Bragg grating array interfere in the coupler, so that the amplitude of each spectral line component output by the amplitude controller satisfies the amplitude of the Fourier coefficient of the even-function waveform optical pulse |F _n |, while making the phase P _n of each spectral line component output by the amplitude controller be an integer multiple of 2π.

(3) Output: According to the principle of Fourier transform, the signal after interference is an even function waveform optical pulse in the time domain, and is output from the port D of the coupler.

The wavelength interval of the optical frequency comb in the above-mentioned step (1) is the same, the amplitude of each spectral line is equal or different, the phase relationship is fixed, there are at least two wavelength components, and the time domain is a periodic optical pulse.

和θ_n由偶函数波形光脉冲各条谱线的幅度|F_n|、耦合器的分光比α:1-α、光纤布拉格光栅的反射率R、输入的光学频率梳的各条谱线复振幅的幅度|S_n|及谱线复振幅的相位ψ_n共同决定：The phase shift produced by the fiber Bragg grating array in the above-mentioned step (2-2) to each spectral line of the two-way signal

and θ _n are determined by the amplitude |F _n | of each spectral line of the even function waveform optical pulse, the splitting ratio of the coupler α:1-α, the reflectivity R of the fiber Bragg grating, and the complexities of each spectral line of the input optical frequency comb. The magnitude |S _n | of the amplitude and the phase ψ _n of the complex amplitude of the spectral line are jointly determined:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位等于2π的整数倍，如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-3) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device, the reflectivity R of the fiber Bragg grating, and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift

Determined jointly with θ _n , the phase of each spectral line component output by the amplitude controller is equal to an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

The above-mentioned even function waveform optical pulses are periodic Gaussian optical pulses, periodic triangular optical pulses, periodic bilateral exponential optical pulses, periodic full-wave cosine optical pulses, periodic half-wave cosine optical pulses, even A function waveform light pulse or an even function waveform light pulse whose amplitudes of adjacent pulses can be independently controlled.

The interference of the two-way signals in the above-mentioned steps (2-3) in the coupler makes the spectral line spacing of the output spectrum twice the spectral line spacing of the input optical frequency comb, and the port D of the coupler outputs the repetition frequency Multiplied even function waveform light pulse.

The interference of the two-way signals in the above-mentioned steps (2-3) in the coupler makes the output spectrum have two groups of spaced spectral lines respectively satisfying the amplitude of the Fourier coefficient of the even function waveform light pulse with different peak values, Then the port D of the coupler outputs even-function waveform optical pulses whose amplitudes of adjacent pulses can be independently controlled.

和θ_n，则反射回耦合器的两路信号发生干涉后，输出信号的频谱相位P_n为2π的整数倍，频谱幅度为偶函数波形光脉冲的傅里叶系数的幅度|F_n|，根据傅里叶变换的原理，时域输出为偶函数波形的任意波形光脉冲。The working principle of the present invention is as follows: adopt the structure of double-array fiber Bragg grating, use the narrow-band fiber Bragg grating as a narrow-band filter to filter each spectral line separately and control it independently, and use the fiber stretcher to introduce phase shift to adjust each spectral line. The phase of the spectral lines makes the spectrum amplitude change as expected after the two signals reflected back to the coupler interfere, and an arbitrary waveform optical pulse with an even function waveform can be output. If the initial phase of the input signal is ψ _n , the splitting ratio of the coupler is α:1-α, the reflectivity of the fiber Bragg grating is R, and the phase P _n of the interference signal reflected back to the coupler is an integer multiple of 2π, the amplitude The spectrum is the amplitude spectrum |F _n | of the even function waveform optical pulse, and the phase shift of each spectral line of the two signals can be calculated, and each fiber stretcher of the two arrays can be adjusted to obtain the corresponding phase shift of the two signals

and θ _n , after the two signals reflected back to the coupler interfere, the spectral phase P _n of the output signal is an integer multiple of 2π, and the spectral amplitude is the amplitude |F _n | of the Fourier coefficient of the even function waveform optical pulse, According to the principle of Fourier transform, the output in the time domain is an arbitrary waveform optical pulse with an even function waveform.

The advantages and beneficial effects of the present invention are: 1. Since the reflectivity of the fiber Bragg grating is difficult to adjust in real time, the existing arbitrary waveform generator utilizing the fiber Bragg grating needs to use an optical attenuator to dynamically change the amplitude of the spectrum, while The double-array fiber Bragg grating shaping structure of the present invention can continuously and accurately change the size of the spectral amplitude without using an optical attenuator and only using a fiber stretcher, so as to realize dynamic adjustment of the spectral amplitude; 2. Existing amplitude modulators Its structure is more complex and not all-fiber, but the structure of dual-array fiber Bragg grating is all-fiber, with simple structure, low loss, and easy coupling with other optical devices; 3. Since it implements progressive spectrum control, it can Output arbitrary waveform optical pulses with even function waveforms; 4. The bandwidth of shaping can be increased by increasing the wavelength interval between adjacent gratings or increasing the number of gratings, so that the bandwidth of the device can be easily upgraded.

(4) Description of drawings:

FIG. 1 is a block diagram of an overall device of an optical pulse shaper based on a dual-array fiber grating according to the present invention.

FIG. 2 is a schematic structural diagram of an amplitude controller in an optical pulse shaper based on a dual-array fiber grating according to the present invention.

Fig. 3 is the working effect schematic diagram of embodiment 1 in a kind of optical pulse shaper based on double-array fiber gratings involved in the present invention (wherein Fig. 3-1 is the time-domain waveform diagram of the input optical frequency comb, Fig. 3-2 is the amplitude spectrum and phase spectrum of the input optical frequency comb, and Figure 3-3 is the amplitude spectrum of the two signals reflected by two fiber Bragg grating arrays and the amplitude spectrum of the output periodic Gaussian pulse, and Figure 3-4 is the two The phase shift spectrum generated by the fiber Bragg grating array on the reflected two-way signal and the phase spectrum of the output periodic Gaussian pulse, Figure 3-5 is the output periodic Gaussian pulse).

Fig. 4 is the schematic diagram of the working effect of Embodiment 2 in a kind of optical pulse shaper based on double-array fiber grating according to the present invention (wherein Fig. 4-1 is the time-domain waveform diagram of the input optical frequency comb, Fig. 4-2 is the amplitude spectrum and phase spectrum of the input optical frequency comb, and Figure 4-3 is the amplitude spectrum of the two signals reflected by two fiber Bragg grating arrays and the amplitude spectrum of the output periodic triangular pulse, and Figure 4-4 is the two The phase shift spectrum generated by the fiber Bragg grating array on the reflected two-way signals and the phase spectrum of the output periodic triangular pulse, Figure 4-5 is the output periodic triangular pulse).

Fig. 5 is a schematic diagram of the working effect of Embodiment 3 in a kind of optical pulse shaper based on double-array fiber gratings according to the present invention (wherein Fig. 5-1 is a time-domain waveform diagram of an input optical frequency comb, and Fig. 5-2 is the magnitude spectrum and phase spectrum of the input optical frequency comb, Fig. 5-3 is the magnitude spectrum of the two signals reflected by two fiber Bragg grating arrays and the magnitude spectrum of the output periodic bilateral exponential pulse, and Fig. 5-4 is the magnitude spectrum of the two The phase shift spectrum generated by a fiber Bragg grating array on the reflected two-way signals and the phase spectrum of the output periodic double-sided exponential pulse, Figure 5-5 is the output periodic double-sided exponential pulse).

Fig. 6 is a schematic diagram of the working effect of Embodiment 4 in an optical pulse shaper based on a dual-array fiber grating according to the present invention (wherein Fig. 6-1 is a time-domain waveform diagram of an input optical frequency comb, and Fig. 6-2 is the amplitude spectrum and phase spectrum of the input optical frequency comb, and Figure 6-3 is the amplitude spectrum of the two signals reflected by two fiber Bragg grating arrays and the output amplitude spectrum of the periodic Gaussian pulse whose repetition frequency is multiplied to 25GHz, Fig. 6-4 is the phase shift spectrum generated by two fiber Bragg grating arrays for the reflected two signals and the phase spectrum of the periodic Gaussian pulse whose output repetition frequency is multiplied to 25GHz. Figure 6-5 is the output repetition frequency multiplied to 25GHz periodic Gaussian pulse).

Fig. 7 is a schematic diagram of the working effect of Embodiment 5 in an optical pulse shaper based on a dual-array fiber grating according to the present invention (Fig. 7-1 is a time-domain waveform diagram of an input optical frequency comb, and Fig. 7-2 is The amplitude spectrum and phase spectrum of the input optical frequency comb, Figure 7-3 shows the amplitude spectrum of the two signals reflected by the two fiber Bragg grating arrays and the normalized amplitude of the output adjacent pulses are 0.5 and 1 periodicity The amplitude spectrum of the Gaussian pulse. Figure 7-4 shows the phase shift spectrum of the two reflected signals produced by the two fiber Bragg grating arrays and the output of the periodic Gaussian pulse whose normalized amplitudes of adjacent pulses are 0.5 and 1 respectively. Phase spectrum, Fig. 7-5 is a periodic Gaussian pulse whose normalized amplitudes of adjacent pulses are 0.5 and 1 respectively).

Among them: 1 is an optical frequency comb source, 2 is an optical isolator, 3 is a coupler, 4-1 is the first fiber Bragg grating array, and 4-2 is the second fiber Bragg grating array.

(5) Specific implementation methods:

The coupler described in the embodiment is a 3dB coupler, that is, a coupler with a splitting ratio of 1:1.

Embodiment 1: a kind of optical pulse shaper based on double array fiber grating, it is characterized in that it is made up of optical frequency comb source 1, optical isolator 2 and amplitude controller, the output end of optical frequency comb source 1 is connected optical isolator 2, the output of the optical isolator 2 is connected to the input of the amplitude controller, and the output of the amplitude controller outputs periodic Gaussian light pulses; said amplitude controller consists of two fiber Bragg grating arrays 4-1 and 4-2 and coupler 3. Port A of coupler 3 is connected to the output end of optical isolator 2. Port B and port C of coupler 3 are respectively connected to two fiber Bragg grating arrays 4-1 and 4-2. The port D of the device 3, that is, the output end of the amplitude controller, outputs periodic Gaussian light pulses; the fiber Bragg grating array is composed of 21 fiber Bragg gratings and 21 fiber stretchers arranged at intervals.

The central reflection wavelengths λ _n of the corresponding Fiber Bragg Gratings in the above-mentioned two Fiber Bragg Grating arrays 4-1 and 4-2 are the same, and the central reflection wavelengths of two adjacent Fiber Bragg Gratings in each Fiber Bragg Grating array The difference of λ _n is the same, both are 0.1nm, and the reflectivity R of all fiber Bragg gratings is the same, both are 99%.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in source 1 is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: the optical frequency comb source 1 sends out the optical frequency comb, and the optical frequency comb is input from the port A of the coupler 3 through the optical isolator 2;

(2) Amplitude control:

(2-1) Light splitting: the input optical frequency comb is divided into two signals by the coupler 3, which are input into two fiber Bragg grating arrays 4-1 and 4-2 from port B and port C respectively;

和θ_n(见图3-4中前两个图形)，

和θ_n的取值见表1，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同，两路信号的各条谱线的幅度下降为F_1n和F_2n(见图3-3中前两个图形)，F_1n和F_2n的取值见表1；(2-2) Phase adjustment: the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays 4-1 and 4-2 select the spectral line equal to its central reflection wavelength λ _n , and adjust the two fiber Bragg gratings respectively at the same time Each fiber stretcher in the grating array realizes the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2, so that the fiber Bragg grating arrays 4-1 and 4-2 pair The phase shifts generated by each spectral line of the two signals are respectively

and θ _n (see the first two graphs in Figure 3-4),

The values of and θ _n are shown in Table 1. At this time, the profiles of the amplitude spectra of the two signals remain unchanged, which are the same as the input optical frequency comb, and the amplitudes of each spectral line of the two signals decrease to F _1n and F _2n (see The first two graphs in Figure 3-3), the values of F _1n and F _2n are shown in Table 1;

(2-3) Interference: The two-way signals reflected by the fiber Bragg grating arrays 4-1 and 4-2 interfere at the coupler 3, so that the amplitude of each spectral line component output by the amplitude controller meets the requirements of the periodic Gaussian optical pulse. The amplitude of the Fourier coefficient |F _n | (see the third figure in Figure 3-3), the value of |F _n | is shown in Table 1, and at the same time, the phase P _n of each spectral line component output by the amplitude controller is Integer multiples of 2π (see the third graph in Figure 3-4), see Table 1 for the value of P _n ;

(3) Output: According to the principle of Fourier transform, the signal after interference is a periodic Gaussian light pulse in the time domain (see Figure 3-5), which is output from port D of the coupler 3 .

的光脉冲(见图3-1)，其中c为真空中的光速，λ₀为光学频率梳源1的中心波长，为1550nm，T为时域上光脉冲的周期，为80ps。The wavelength interval of the optical frequency comb (see Figure 3-2) in the above-mentioned step (1) is Δλ=0.1nm, the profile of the amplitude spectrum is the equal amplitude of each spectral line, and the phase relationship is the phase between each spectral line The difference is 0, there are 101 wavelength components, and the repetition frequency in the time domain is

(see Figure 3-1), where c is the speed of light in vacuum, λ ₀ is the center wavelength of the optical frequency comb source 1, which is 1550nm, and T is the period of the optical pulse in the time domain, which is 80ps.

The phase shift produced by the fiber Bragg grating arrays 4-1 and 4-2 in the above-mentioned step (2-2) to each spectral line of the two signals and θ _n are determined by the amplitude |F _n | of each spectral line of the periodic Gaussian optical pulse, the splitting ratio α:1-α of the coupler 3, the reflectivity R of the fiber Bragg grating, and each spectral line of the input optical frequency comb The magnitude |S _n | of the complex amplitude and the phase ψ _n of the complex amplitude of the spectral line (the values of |S _n | and ψ _n are shown in Table 1) are jointly determined:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位为2π的整数倍，如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-3) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device 3, the reflectivity R of the fiber Bragg grating, and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift

Determined jointly with θ _n , the phase of each spectral line component output by the amplitude controller is an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

Table 1 shows the values of the wavelength, amplitude and phase of each spectral line of the optical frequency comb input in Embodiment 1, and the values of each spectral line of the two signals reflected by the two fiber Bragg grating arrays 4-1 and 4-2. Amplitude and the value of the phase shift produced by the two fiber Bragg grating arrays 4-1 and 4-2 on the spectral lines of the reflected two signals, the amplitude and phase value of the periodic Gaussian optical pulse output from the amplitude controller . where n is the order of the Fourier coefficient, λ _n is the wavelength value of each spectral line of the input optical frequency comb, and is also the central reflection wavelength corresponding to each fiber Bragg grating, |S _n | and ψ _n are the input The amplitude and phase value of each spectral line of the optical frequency comb, F _1n is the amplitude value of each spectral line of the signal reflected by the first fiber Bragg grating array 4-1, F _2n is the second fiber Bragg grating The amplitude value of each spectral line of the signal reflected by the array 4-2, is the phase shift produced by the first fiber Bragg grating array 4-1 to each spectral line of the reflected signal, θ _n is the phase shift produced by the second fiber Bragg grating array 4-1 to each spectral line of the reflected signal , |F _n | is the amplitude value of the Fourier coefficient of the periodic Gaussian light pulse output from the amplitude controller, and P _n is the phase value of the Fourier coefficient of the periodic Gaussian light pulse output from the amplitude controller.

Table 1

Embodiment 2: a kind of optical pulse shaper based on double-array fiber grating, it is characterized in that it is made up of optical frequency comb source 1, optical isolator 2 and amplitude controller, the output end of optical frequency comb source 1 connects optical isolator 2, the output of the optical isolator 2 is connected to the input of the amplitude controller, and the output of the amplitude controller outputs periodic triangular light pulses; said amplitude controller consists of two fiber Bragg grating arrays 4-1 and 4-2 and coupler 3. Port A of coupler 3 is connected to the output end of optical isolator 2. Port B and port C of coupler 3 are respectively connected to two fiber Bragg grating arrays 4-1 and 4-2. The port D of the device 3, that is, the output end of the amplitude controller, outputs periodic triangular light pulses; the fiber Bragg grating array is composed of 21 fiber Bragg gratings and 21 fiber stretchers arranged at intervals.

The central reflection wavelengths λ _n of the corresponding Fiber Bragg Gratings in the above-mentioned two Fiber Bragg Grating arrays 4-1 and 4-2 are the same, and the central reflection wavelengths of two adjacent Fiber Bragg Gratings in each Fiber Bragg Grating array The difference of λ _n is the same, both are 0.36nm, and the reflectivity R of all fiber Bragg gratings is the same, both are 90%.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in source 1 is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: the optical frequency comb source 1 sends out the optical frequency comb, and the optical frequency comb is input from the port A of the coupler 3 through the optical isolator 2;

(2) Amplitude control:

(2-1) Light splitting: the input optical frequency comb is divided into two signals by the coupler 3, which are input into two fiber Bragg grating arrays 4-1 and 4-2 from port B and port C respectively;

和θ_n(见图4-4中前两个图形)，

和θ_n的取值见表2，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同，两路信号的各条谱线的幅度下降为F_1n和F_2n(见图4-3中前两个图形)，F_1n和F_2n的取值见表2；(2-2) Phase adjustment: the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays 4-1 and 4-2 select the spectral line equal to its central reflection wavelength λ _n , and adjust the two fiber Bragg gratings respectively at the same time Each fiber stretcher in the grating array realizes the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2, so that the fiber Bragg grating arrays 4-1 and 4-2 pair The phase shifts generated by each spectral line of the two signals are respectively

and θ _n (see the first two graphs in Figure 4-4),

and the values of θ _n are shown in Table 2. At this time, the profiles of the amplitude spectra of the two signals remain unchanged, which are the same as the input optical frequency comb, and the amplitudes of each spectral line of the two signals decrease to F _1n and F _2n (see The first two graphs in Figure 4-3), the values of F _1n and F _2n are shown in Table 2;

(2-3) Interference: The two-way signals reflected by the fiber Bragg grating arrays 4-1 and 4-2 interfere in the coupler 3, so that the amplitude of each spectral line component output by the amplitude controller meets the requirements of the periodic triangular optical pulse. The magnitude of the Fourier coefficient |F _n | (see the third graph in Figure 4-3), the value of |F _n | is shown in Table 2, and at the same time, the phase P _n of each spectral line component output by the amplitude controller is Integer multiples of 2π (see the third graph in Figure 4-4), the value of P _n is shown in Table 2;

(3) Output: According to the principle of Fourier transform, the signal after interference is a periodic triangular light pulse in the time domain (see Figure 4-5), and is output from port D of the coupler 3 .

的光脉冲(见图4-1)，其中c为真空中的光速，λ₀为光学频率梳源1的中心波长，为1310nm，T为时域上光脉冲的周期，为16ps。The wavelength interval of the optical frequency comb (see Figure 4-2) in the above-mentioned step (1) is Δλ=0.36nm, the profile of the amplitude spectrum is that the ratio of the amplitude of adjacent spectral lines is 1:0.7, and the phase relationship is that the phase profile is Parabolic, with 85 wavelength components, the repetition frequency in the time domain is

(see Figure 4-1), where c is the speed of light in vacuum, λ ₀ is the center wavelength of the optical frequency comb source 1, which is 1310nm, and T is the period of the optical pulse in the time domain, which is 16ps.

和θ_n由周期性三角光脉冲各条谱线的幅度|F_n|、耦合器3的分光比α:1-α、光纤布拉格光栅的反射率、输入的光学频率梳的各条谱线复振幅的幅度|S_n|及谱线复振幅的相位ψ_n共同决定：The phase shift produced by the fiber Bragg grating array in the above-mentioned step (2-2) to each spectral line of the two-way signal

and θ _n are composed of the amplitude |F _n | of each spectral line of the periodic triangular optical pulse, the splitting ratio α:1-α of the coupler 3, the reflectivity of the fiber Bragg grating, and the complexities of each spectral line of the input optical frequency comb. The magnitude |S _n | of the amplitude and the phase ψ _n of the complex amplitude of the spectral line are jointly determined:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移

和θ_n(|S_n|和ψ_n取值如表2所示)共同决定的，幅度控制器输出的各个谱线成分的相位为2π的整数倍，如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-3) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device 3, the reflectivity R of the fiber Bragg grating and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift

and θ _n (the values of |S _n | and ψ _n are shown in Table 2), the phase of each spectral line component output by the amplitude controller is an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

为第一个光纤布拉格光栅阵列4-1对反射的信号的各条谱线产生的相移，θ_n为第二个光纤布拉格光栅阵列4-2对反射的信号的各条谱线产生的相移，|F_n|为从幅度控制器输出的周期性三角光脉冲的傅里叶系数的幅度值，P_n为从幅度控制器输出的周期性三角光脉冲的傅里叶系数的相位值。Table 2 shows the values of the wavelength, amplitude and phase of each spectral line of the optical frequency comb input in embodiment 2, and the values of each spectral line of the two signals reflected by the two fiber Bragg grating arrays 4-1 and 4-2. Amplitude and the value of the phase shift produced by the two fiber Bragg grating arrays 4-1 and 4-2 on the spectral lines of the reflected two signals, the amplitude and phase value of the periodic triangular optical pulse output from the amplitude controller . where n is the order of the Fourier coefficient, λ _n is the wavelength value of each spectral line of the input optical frequency comb, and is also the central reflection wavelength corresponding to each fiber Bragg grating, |S _n | and ψ _n are the input The amplitude and phase value of each spectral line of the optical frequency comb, F _1n is the amplitude value of each spectral line of the signal reflected by the first fiber Bragg grating array 4-1, F _2n is the second fiber Bragg grating The amplitude value of each spectral line of the signal reflected by the array 4-2,

is the phase shift produced by the first fiber Bragg grating array 4-1 to each spectral line of the reflected signal, θ _n is the phase shift produced by the second fiber Bragg grating array 4-2 to each spectral line of the reflected signal |F _n | is the amplitude value of the Fourier coefficient of the periodic triangular light pulse output from the amplitude controller, and P _n is the phase value of the Fourier coefficient of the periodic triangular light pulse output from the amplitude controller.

Table 2

Embodiment 3: A kind of optical pulse shaper based on double array fiber grating, it is characterized in that it is made up of optical frequency comb source 1, optical isolator 2 and amplitude controller, the output end of optical frequency comb source 1 is connected to optical isolator 2, the output of the optical isolator 2 is connected to the input of the amplitude controller, and the output of the amplitude controller outputs periodic double-sided exponential light pulses; the said amplitude controller consists of two fiber Bragg grating arrays 4-1 Composed of 4-2 and coupler 3, port A of coupler 3 is connected to the output end of optical isolator 2, port B and port C of coupler 3 are respectively connected to two fiber Bragg grating arrays 4-1 and 4-2, The port D of the coupler 3, that is, the output end of the amplitude controller, outputs periodic bilateral exponential light pulses; the fiber Bragg grating array is composed of 41 fiber Bragg gratings and 41 fiber stretchers arranged at intervals.

The central reflection wavelengths λ _n of the corresponding Fiber Bragg Gratings in the above-mentioned two Fiber Bragg Grating arrays 4-1 and 4-2 are the same, and the central reflection wavelengths of two adjacent Fiber Bragg Gratings in each Fiber Bragg Grating array The difference of λ _n is the same, both are 1nm, and the reflectivity R of all fiber Bragg gratings is the same, both are 80%.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in source 1 is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: the optical frequency comb source 1 sends out the optical frequency comb, and the optical frequency comb is input from the port A of the coupler 3 through the optical isolator 2;

(2) Amplitude control:

(2-1) Light splitting: the input optical frequency comb is divided into two signals by the coupler 3, which are input into two fiber Bragg grating arrays 4-1 and 4-2 from port B and port C respectively;

和θ_n(见图5-4中前两个图形)，

和θ_n的取值见表3，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同，两路信号的各条谱线的幅度下降为F_1n和F_2n(见图5-3中前两个图形)，F_1n和F_2n的取值见表3；(2-2) Phase adjustment: the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays 4-1 and 4-2 select the spectral line equal to its central reflection wavelength λ _n , and adjust the two fiber Bragg gratings respectively at the same time Each fiber stretcher in the grating array realizes the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2, so that the fiber Bragg grating arrays 4-1 and 4-2 pair The phase shifts generated by each spectral line of the two signals are respectively

and θ _n (see the first two graphs in Figure 5-4),

and the values of θ _n are shown in Table 3. At this time, the profiles of the amplitude spectra of the two signals remain unchanged, which are the same as the input optical frequency comb, and the amplitudes of each spectral line of the two signals decrease to F _1n and F _2n (see The first two graphs in Figure 5-3), the values of F _1n and F _2n are shown in Table 3;

(2-3) Interference: The two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2 interfere in the coupler 3, so that the amplitude of each spectral line component output by the amplitude controller satisfies the periodic double-sided exponential optical pulse The magnitude of the Fourier coefficient |F _n | (see the third graph in Figure 5-3), the value of |F _n | is shown in Table 3, and at the same time, the phase P _n of each spectral line component output by the amplitude controller is an integer multiple of 2π (see the third figure in Figure 5-4), and the value of P _n is shown in Table 3;

(3) Output: According to the principle of Fourier transform, the signal after interference is a periodic double-sided exponential light pulse in the time domain (see Figure 5-5), which is output from port D of the coupler 3 .

The wavelength interval of the optical frequency comb in the above-mentioned step (1) (see Figure 5-2) is Δλ=1nm, the profile of the amplitude spectrum is Gaussian, and the phase relationship is that the phase difference between adjacent spectral lines is 0, There are 81 wavelength components, and the repetition frequency in the time domain is (see Figure 5-1), where c is the speed of light in vacuum, λ ₀ is the center wavelength of the optical frequency comb source 1, which is 1510nm, and T is the period of the light pulse in the time domain, which is 8ps.

和θ_n由周期性双边指数脉冲各条谱线的幅度|F_n|、耦合器3的分光比α:1-α、光纤布拉格光栅的反射率R、输入的光学频率梳的各条谱线复振幅的幅度|S_n|及谱线复振幅的相位ψ_n共同决定，|S_n|和ψ_n取值见表3：The phase shift produced by the fiber Bragg grating array in the above-mentioned step (2-2) to each spectral line of the two-way signal

and θ _n are determined by the amplitude |F _n | of each spectral line of the periodic double-sided exponential pulse, the splitting ratio α:1-α of the coupler 3, the reflectivity R of the fiber Bragg grating, and each spectral line of the input optical frequency comb The magnitude |S _n | of the complex amplitude and the phase ψ _n of the complex amplitude of the spectral line are jointly determined, and the values of |S _n | and ψ _n are shown in Table 3:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移

和θ_n(|S_n|和ψ_n取值如表3所示)共同决定的，幅度控制器输出的各个谱线成分的相位为2π的整数倍，如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-3) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device 3, the reflectivity R of the fiber Bragg grating, and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift

and θ _n (the values of |S _n | and ψ _n are shown in Table 3), the phase of each spectral line component output by the amplitude controller is an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

为第一个光纤布拉格光栅阵列4-1对反射的信号各条谱线的产生的相移，θ_n为第二个光纤布拉格光栅阵列4-2对反射的信号的各条谱线产生的相移，|F_n|为从幅度控制器输出的周期性双边指数光脉冲的傅里叶系数的幅度值，P_n为从幅度控制器输出的周期性双边指数光脉冲的傅里叶系数的相位值。Table 3 is the wavelength, amplitude and phase value of each spectral line of the optical frequency comb input in embodiment 3, the amplitude and value of each spectral line of the two signals reflected by the two fiber Bragg grating arrays 41 and 4-2 The value of the phase shift generated by the two fiber Bragg grating arrays 4-1 and 4-2 on the spectral lines of the reflected two-way signals, and the amplitude and phase values of the periodic double-sided exponential light pulse output from the amplitude controller. where n is the order of the Fourier coefficient, λ _n is the wavelength value of each spectral line of the input optical frequency comb, and is also the central reflection wavelength corresponding to each fiber Bragg grating, |S _n | and ψ _n are the input The amplitude and phase value of each spectral line of the optical frequency comb, F _1n is the amplitude value of each spectral line of the signal reflected by the first fiber Bragg grating array 4-1, F _2n is the second fiber Bragg grating The amplitude value of each spectral line of the signal reflected by the array 4-2,

is the phase shift produced by the first fiber Bragg grating array 4-1 to each spectral line of the reflected signal, θ _n is the phase shift produced by the second fiber Bragg grating array 4-2 to each spectral line of the reflected signal |F _n | is the amplitude value of the Fourier coefficient of the periodic double-sided exponential light pulse output from the amplitude controller, and P _n is the phase of the Fourier coefficient of the periodic double-sided exponential light pulse output from the amplitude controller value.

table 3

Embodiment 4: A kind of optical pulse shaper based on double array fiber grating, it is characterized in that it is made up of optical frequency comb source 1, optical isolator 2 and amplitude controller, the output end of optical frequency comb source 1 is connected to optical isolator 2, the output of the optical isolator 2 is connected to the input of the amplitude controller, and the output of the amplitude controller outputs a periodic Gaussian optical pulse whose repetition rate is multiplied to 25 GHz; the said amplitude controller consists of two optical fiber Bragg Composed of grating arrays 4-1 and 4-2 and coupler 3, port A of coupler 3 is connected to the output end of optical isolator 2, port B and port C of coupler 3 are respectively connected to two fiber Bragg grating arrays 4-1 And 4-2, the port D of the coupler 3 is the output end output of the amplitude controller and the repetition frequency is multiplied as the periodic Gaussian light pulse of 25GHz; said fiber Bragg grating array is made of 45 fiber Bragg gratings and 45 optical fibers arranged at intervals.

The central reflection wavelengths λ _n of the corresponding Fiber Bragg Gratings in the above-mentioned two Fiber Bragg Grating arrays 4-1 and 4-2 are the same, and the central reflection wavelengths of two adjacent Fiber Bragg Gratings in each Fiber Bragg Grating array The difference of λ _n is the same, both are 0.04nm, and the reflectivity R of all fiber Bragg gratings is the same, both are 75%.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in source 1 is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: the optical frequency comb source 1 sends out the optical frequency comb, and the optical frequency comb is input from the port A of the coupler 3 through the optical isolator 2;

(2) Amplitude control:

(2-1) Light splitting: the input optical frequency comb is divided into two signals by the coupler 3, which are input into two fiber Bragg grating arrays 4-1 and 4-2 from port B and port C respectively;

和θ_n(见图6-4中前两个图形)，和θ_n的取值见表4，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同，两路信号的各条谱线的幅度下降为F_1n和F_2n(见图6-3中前两个图形)，F_1n和F_2n的取值见表4；(2-2) Phase adjustment: the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays 4-1 and 4-2 select the spectral line equal to its central reflection wavelength λ _n , and adjust the two fiber Bragg gratings respectively at the same time Each fiber stretcher in the grating array realizes the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2, so that the fiber Bragg grating arrays 4-1 and 4-2 pair The phase shifts generated by each spectral line of the two signals are respectively

and θ _n (see the first two graphs in Figure 6-4), and the values of θ _n are shown in Table 4. At this time, the profiles of the amplitude spectra of the two signals remain unchanged, which are the same as the input optical frequency comb, and the amplitudes of each spectral line of the two signals decrease to F _1n and F _2n (see The first two graphs in Figure 6-3), the values of F _1n and F _2n are shown in Table 4;

(2-3) Interference: The two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2 interfere in the coupler 3, so that the amplitude of each spectral line component output by the amplitude controller meets the requirement that the repetition frequency is multiplied to 25 GHz The amplitude |F _n | of the Fourier coefficient of the periodic Gaussian optical pulse (see the third figure in Figure 6-3), the value of |F _n | is shown in Table 4, and at the same time, each spectral line output by the amplitude controller The phase P _n of the components is an integer multiple of 2π (see the third figure in Figure 6-4), and the value of P _n is shown in Table 4;

(3) Output: According to the principle of Fourier transform, the signal time domain after interference is a periodic Gaussian pulse whose repetition frequency is multiplied to 25 GHz (see Figure 6-5), and is output from port D of coupler 3 .

的光脉冲(见图6-1)，其中c为真空中的光速，λ₀为光学频率梳源1的中心波长，为980nm，T为时域上的光脉冲的周期，为80ps。The wavelength interval of the optical frequency comb (see Figure 6-2) in the above-mentioned step (1) is Δλ=0.04nm, the profile of the amplitude spectrum is the equal amplitude of each spectral line, and the phase relationship is the phase between each spectral line The difference is 0, there are 51 wavelength components, and the repetition frequency in the time domain is

(see Figure 6-1), where c is the speed of light in vacuum, λ ₀ is the center wavelength of the optical frequency comb source 1, which is 980nm, and T is the period of the light pulse in the time domain, which is 80ps.

和θ_n由重复频率倍增为25GHz的周期性高斯光脉冲各条谱线的幅度|F_n|、耦合器3的分光比α:1-α、光纤布拉格光栅的反射率R、输入的光学频率梳的各条谱线复振幅的幅度|S_n|及谱线复振幅的相位ψ_n(|S_n|和ψ_n取值如表4所示)共同决定：The phase shift produced by the fiber Bragg grating array in the above-mentioned step (2-2) to each spectral line of the two-way signal

and θ _n are multiplied by the repetition frequency to the amplitude |F _n | of each spectral line of the periodic Gaussian optical pulse of 25 GHz, the splitting ratio α:1-α of the coupler 3, the reflectivity R of the fiber Bragg grating, and the input optical frequency The amplitude |S _n | of the complex amplitude of each spectral line of the comb and the phase ψ _n of the complex amplitude of the spectral line (the values of |S _n | and ψ _n are shown in Table 4) are jointly determined:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位为2π的整数倍,如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-3) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device 3, the reflectivity R of the fiber Bragg grating, and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift

Determined jointly with θ _n , the phase of each spectral line component output by the amplitude controller is an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

为第一个光纤布拉格光栅阵列4-1对反射的信号的各条谱线产生的相移，θ_n为第二个光纤布拉格光栅阵列4-2对反射的信号的各条谱线产生的相移，|F_n|为从幅度控制器输出的重复频率倍增为25GHz的周期性高斯光脉冲的傅里叶系数的幅度值，P_n为从幅度控制器输出的重复频率倍增为25GHz的周期性高斯光脉冲的傅里叶系数的相位值。Table 4 shows the values of the wavelength, amplitude and phase of each spectral line of the optical frequency comb input in embodiment 4, and the values of each spectral line of the two signals reflected by the two fiber Bragg grating arrays 4-1 and 4-2. Amplitude and the value of the phase shift produced by the two fiber Bragg grating arrays 4-1 and 4-2 on the spectral lines of the reflected two signals, the repetition frequency output from the amplitude controller is multiplied into a periodic Gaussian optical pulse of 25GHz The magnitude and phase values of . where n is the order of the Fourier coefficient, λ _n is the wavelength value of each spectral line of the input optical frequency comb, and is also the central reflection wavelength corresponding to each fiber Bragg grating, |S _n | and ψ _n are the input The amplitude and phase value of each spectral line of the optical frequency comb, F _1n is the amplitude value of each spectral line of the signal reflected by the first fiber Bragg grating array 4-1, F _2n is the second fiber Bragg grating The amplitude value of each spectral line of the signal reflected by the array 4-2,

is the phase shift produced by the first fiber Bragg grating array 4-1 to each spectral line of the reflected signal, θ _n is the phase shift produced by the second fiber Bragg grating array 4-2 to each spectral line of the reflected signal |F _n | is the amplitude value of the Fourier coefficient of the periodic Gaussian light pulse output from the amplitude controller whose repetition frequency is doubled to 25GHz, and P _n is the periodicity of the repetition frequency output from the amplitude controller doubled to 25GHz Phase values of the Fourier coefficients of a Gaussian light pulse.

Table 4

Embodiment 5: A kind of optical pulse shaper based on double array fiber grating, it is characterized in that it is made up of optical frequency comb source 1, optical isolator 2 and amplitude controller, the output end of optical frequency comb source 1 is connected to optical isolator 2, the output of the optical isolator 2 is connected to the input of the amplitude controller, and the output of the amplitude controller outputs the periodic Gaussian optical pulses whose normalized amplitudes of adjacent pulses are respectively 0.5 and 1; said amplitude The controller consists of two fiber Bragg grating arrays 4-1 and 4-2 and a coupler 3, the port A of the coupler 3 is connected to the output end of the optical isolator 2, and the port B and port C of the coupler 3 are respectively connected to two The fiber Bragg grating arrays 4-1 and 4-2, the port D of the coupler 3, that is, the output end of the amplitude controller, outputs the periodic Gaussian light pulses whose normalized amplitudes of adjacent pulses are respectively 0.5 and 1; said fiber Bragg grating The grating array is composed of 33 fiber Bragg gratings and 33 fiber stretchers arranged at intervals.

The central reflection wavelengths λ _n of the corresponding Fiber Bragg Gratings in the above-mentioned two Fiber Bragg Grating arrays 4-1 and 4-2 are the same, and the central reflection wavelengths of two adjacent Fiber Bragg Gratings in each Fiber Bragg Grating array The difference of λ _n is the same, both are 0.1nm, and the reflectivity R of all fiber Bragg gratings is the same, both are 99%.

The central reflection wavelength λ _n of the fiber Bragg grating in the above-mentioned fiber Bragg grating array is equal to the wavelength of the corresponding spectral component of the optical frequency comb source, and the number of fiber Bragg gratings in each fiber Bragg grating array is the same as the selected optical frequency comb The number of spectral lines in source 1 is equal.

A kind of working method of the above-mentioned optical pulse shaper based on double array fiber grating, it is characterized in that concrete steps are as follows:

(1) Input: the optical frequency comb source 1 sends out the optical frequency comb, and the optical frequency comb is input from the port A of the coupler 3 through the optical isolator 2;

(2) Amplitude control:

(2-1) Optical splitting: the input optical frequency comb is divided into two signals by the coupler 3, which are input into two fiber Bragg grating arrays 4-1 and 4-2 from port B and port C respectively;

和θ_n(见图7-4中前两个图形)，和θ_n的取值见表5，此时两路信号幅度谱的轮廓保持不变，与输入的光学频率梳相同，两路信号的各条谱线的幅度下降为F_1n和F_2n(见图7-3中前两个图形)，F_1n和F_2n的取值见表5；(2-2) Phase adjustment: the reflection characteristics of each fiber Bragg grating in the two fiber Bragg grating arrays 4-1 and 4-2 select the spectral line equal to its central reflection wavelength λ _n , and adjust the two fiber Bragg gratings respectively at the same time Each fiber stretcher in the grating array realizes the phase adjustment of each spectral line of the two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2, so that the fiber Bragg grating arrays 4-1 and 4-2 pair The phase shifts generated by each spectral line of the two signals are respectively

and θ _n (see the first two graphs in Figure 7-4), and the values of θ _n are shown in Table 5. At this time, the profiles of the amplitude spectra of the two signals remain unchanged, which are the same as the input optical frequency comb, and the amplitudes of each spectral line of the two signals decrease to F _1n and F _2n (see The first two graphs in Figure 7-3), the values of F _1n and F _2n are shown in Table 5;

(2-3) Interference: The two signals reflected by the fiber Bragg grating arrays 4-1 and 4-2 interfere in the coupler 3, so that the amplitude of each spectral line component output by the amplitude controller satisfies the normalization of adjacent pulses The magnitude |F _n | of the Fourier coefficients of the periodic Gaussian light pulses with amplitudes of 0.5 and 1 (see the third graph in Figure 7-3), the value of |F _n | is shown in Table 5, and the amplitude The phase P _n of each spectral line component output by the controller is an integer multiple of 2π (see the third figure in Figure 7-4), and the value of P _n is shown in Table 5;

(3) Output: According to the principle of Fourier transform, the signal after interference in the time domain is a periodic Gaussian optical pulse with the normalized amplitudes of adjacent pulses being 0.5 and 1 respectively (see Figure 7-5), from the coupler 3's Port D output.

的光脉冲(见图7-1)，其中c为真空中的光速，λ₀为光学频率梳源1的中心波长，为1550nm，T为时域上的光脉冲的周期，为80ps。The wavelength interval of the optical frequency comb (see Figure 7-2) in the above-mentioned step (1) is Δλ=0.1nm, the profile of the amplitude spectrum is the equal amplitude of each spectral line, and the phase relationship is the phase between each spectral line The difference is π, there are 81 wavelength components, and the repetition frequency in the time domain is

(see Figure 7-1), where c is the speed of light in vacuum, λ ₀ is the center wavelength of the optical frequency comb source 1, which is 1550nm, and T is the period of the light pulse in the time domain, which is 80ps.

和θ_n由相邻脉冲归一化幅度分别为0.5和1的周期性高斯光脉冲的各条谱线的幅度|F_n|、耦合器3的分光比α:1-α、光纤布拉格光栅的反射率R、输入的光学频率梳的各条谱线复振幅的幅度|S_n|及谱线复振幅的相位ψ_n(|S_n|和ψ_n取值如表5所示)共同决定：The phase shift produced by the fiber Bragg grating array in the above-mentioned step (2-2) to each spectral line of the two-way signal

and θ _n are determined by the amplitude |F _n | of each spectral line of the periodic Gaussian optical pulse with the normalized amplitudes of adjacent pulses being 0.5 and 1 respectively, the splitting ratio α:1-α of the coupler 3, the fiber Bragg grating The reflectivity R, the amplitude |S _n | of the complex amplitude of each spectral line of the input optical frequency comb and the phase ψ _n of the complex amplitude of the spectral line (the values of |S _n | and ψ _n are shown in Table 5) are jointly determined:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>\sqrt{\mathrm{<span\; class="notranslate">\; R\&alpha;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

(n=0, ±1, ±2, ±3...)

和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位P_n是由输入光学频率梳各条谱线的初始相位ψ_n及光纤布拉格光栅阵列对两路信号各条谱线产生的相移和θ_n共同决定的，幅度控制器输出的各个谱线成分的相位为2π的整数倍，如下所示：The amplitude |F _n | of each spectral line component output by the amplitude controller in the above-mentioned step (2-2) is determined by the amplitude |S _n | of each spectral line of the input optical frequency comb, the initial phase ψ _n , the coupling The splitting ratio α:1-α of the device 3, the reflectivity R of the fiber Bragg grating, and the phase shift of each spectral line of the two signals

and θ _n , the phase P _n of each spectral line component output by the amplitude controller is generated by the initial phase ψ _n of each spectral line of the input optical frequency comb and the fiber Bragg grating array for each spectral line of the two signals phase shift Determined jointly with θ _n , the phase of each spectral line component output by the amplitude controller is an integer multiple of 2π, as shown below:

(n=0, ±1, ±2, ±3...), m is an integer.

为第一个光纤布拉格光栅阵列4-1对反射的信号各条谱线的产生的相移，θ_n为第二个光纤布拉格光栅阵列4-2对反射的信号各条谱线产生的相移，|F_n|为从幅度控制器输出的相邻脉冲归一化幅度分别为0.5和1的周期性高斯光脉冲的傅里叶系数的幅度值，P_n为从幅度控制器输出的相邻脉冲归一化幅度分别为0.5和1的周期性高斯光脉冲的傅里叶系数的相位值。Table 5 shows the values of the wavelength, amplitude and phase of each spectral line of the optical frequency comb input in Embodiment 5, and the values of each spectral line of the two signals reflected by the two fiber Bragg grating arrays 4-1 and 4-2. Amplitude and the value of the phase shift produced by the two fiber Bragg grating arrays 4-1 and 4-2 on the spectral lines of the reflected two-way signals, the normalized amplitudes of the adjacent pulses output from the amplitude controller are respectively 0.5 and A value of 1 for the amplitude and phase of the periodic Gaussian light pulse. Where n is the order of the Fourier coefficient, λ _n is the wavelength value of each spectral line of the input optical frequency comb, and is also the central reflection wavelength corresponding to each fiber Bragg grating 5, |S _n | and ψ _n are respectively The amplitude and phase value of each spectral line of the input optical frequency comb, F _1n is the amplitude value of each spectral line of the signal reflected by the first fiber Bragg grating array 4-1, and F _2n is the second fiber Bragg The amplitude value of each spectral line of the signal reflected by the grating array 4-2,

is the phase shift produced by the first fiber Bragg grating array 4-1 to each spectral line of the reflected signal, θ _n is the phase shift produced by the second fiber Bragg grating array 4-2 to each spectral line of the reflected signal , |F _n | is the amplitude value of the Fourier coefficient of the periodic Gaussian light pulse output from the amplitude controller with the normalized amplitudes of adjacent pulses being 0.5 and 1 respectively, and P _n is the adjacent pulse output from the amplitude controller Phase values of the Fourier coefficients of periodic Gaussian light pulses with pulse-normalized amplitudes of 0.5 and 1, respectively.

table 5

Combining the above five embodiments, as in embodiment 1, compared with embodiment 2 and embodiment 3, different phase control is implemented, embodiment 1 outputs periodic Gaussian light pulses, embodiment 2 outputs periodic triangular light pulses, embodiment 2 3 Output periodic bilateral exponential light pulses, the waveforms of the three are different; Embodiment 4 suppresses a spectral line at intervals through phase control, so that the spectral line interval is multiplied, and the repetition frequency of the output Gaussian pulse sequence is multiplied to 25GHz; Embodiment In 5, through phase control, the spectral lines of the output spectrum are controlled at intervals, so that there are two sets of spaced spectral lines in the output spectrum respectively satisfying the amplitude of the Fourier coefficient of the periodic Gaussian light pulse with a peak ratio of 0.5:1, Then the amplitudes of two adjacent pulses within one period of the waveform output in the time domain are different.

To sum up, this scheme utilizes the phase control and interference effect of the dual-array fiber Bragg grating, and introduces phase shift through the fiber stretcher in the two fiber Bragg grating arrays, so that the amplitude of each spectral line after the interference of the two signals changes arbitrarily , and finally output an arbitrary waveform optical pulse with an even function waveform, which can dynamically and continuously change the spectral amplitude line by line, the bandwidth is easy to upgrade, the structure is simple, the loss is small, and it is easy to couple with other optical devices.

Claims (10)

1. shaping of light pulse device based on two array fibre gratings; It is characterized in that it is made up of optical frequency com source, optoisolator and amplitude controller; The output terminal in optical frequency com source connects the input end of optoisolator; The output terminal of optoisolator connects the input end of amplitude controller, the output terminal output even function waveform light pulse of amplitude controller; Said amplitude controller is made up of two Fiber Bragg Grating FBG arrays and coupling mechanism; The port A of coupling mechanism connects the output terminal of optoisolator; The port B of coupling mechanism is connected two Fiber Bragg Grating FBG arrays respectively with port C, and the port D of coupling mechanism is the output terminal output even function waveform light pulse of amplitude controller; Said Fiber Bragg Grating FBG array is spaced by at least two Fiber Bragg Grating FBGs and at least one optical fiber stretcher and constitutes.

2. according to the said a kind of shaping of light pulse device of claim 1, it is characterized in that the foveal reflex wavelength X of corresponding Fiber Bragg Grating FBG in said two Fiber Bragg Grating FBG arrays based on two array fibre gratings _nIdentical, the foveal reflex wavelength X of adjacent two Fiber Bragg Grating FBGs in each Fiber Bragg Grating FBG array _nDifference identical.

3. according to the said a kind of shaping of light pulse device of claim 1, it is characterized in that the foveal reflex wavelength X of Fiber Bragg Grating FBG in the said Fiber Bragg Grating FBG array based on two array fibre gratings _nEquate that with the wavelength of the corresponding spectral components in optical frequency com source the bar number of the spectral line in each Fiber Bragg Grating FBG array in the number of Fiber Bragg Grating FBG and the selected optical frequency com source equates.

4. the method for work of the said shaping of light pulse device based on two array fibre gratings of a claim 1 is characterized in that concrete steps are following:

(1) input: optical frequency com is sent in the optical frequency com source, and optical frequency com is through the port A input of optoisolator from coupling mechanism;

(2) amplitude control:

(2-1) beam split: by coupling mechanism the optical frequency com of importing is divided into two paths of signals, is input to two Fiber Bragg Grating FBG arrays from port B and port C respectively;

(2-2) phase adjusted: the reflection characteristic by each Fiber Bragg Grating FBG in two Fiber Bragg Grating FBG arrays is selected and its foveal reflex wavelength X _nThe spectral line that equates; Regulate each optical fiber stretcher in two Fiber Bragg Grating FBG arrays simultaneously respectively; Realization makes the Fiber Bragg Grating FBG array be respectively the phase shift that each bar spectral line of two paths of signals produces to the phase adjusted by each bar spectral line of two paths of signals of Fiber Bragg Grating FBG array reflection

And θ _n, this moment, the profile of two paths of signals amplitude spectrum remained unchanged, and is identical with the optical frequency com of input.

(2-3) interfere: the two paths of signals by the reflection of Fiber Bragg Grating FBG array interferes at coupling mechanism, makes the amplitude of each spectral line composition that amplitude controller is exported satisfy the amplitude of the Fourier coefficient of even function waveform light pulse | F _n|, the phase place P of each spectral line composition that makes amplitude controller output simultaneously _nIt is the integral multiple of 2 π.

(3) output: according to the principle of Fourier transform, be the light pulse of even function waveform on the signal time domain after the interference, from the port D output of coupling mechanism.

5. according to the method for work of the said a kind of shaping of light pulse device based on two array fibre gratings of claim 4; The wavelength interval that it is characterized in that the optical frequency com in the said step (1) is identical; Each bar spectral line amplitude equates or does not wait; Phase relation is fixed, and has two wavelength components at least, is periodic optical pulse on the time domain.

6. according to the method for work of the said a kind of shaping of light pulse device based on two array fibre gratings of claim 4, it is characterized in that the phase shift that the Fiber Bragg Grating FBG array in the said step (2-2) produces each bar spectral line of two paths of signals

And θ _nAmplitude by each bar spectral line of even function waveform light pulse | F _n|, the splitting ratio α of coupling mechanism: the amplitude of each bar spectral line complex amplitude of the reflectivity R of 1-α, Fiber Bragg Grating FBG, the optical frequency com of input | S _n| and the phase place ψ of spectral line complex amplitude _nCommon decision:

${\mathrm{\&theta;}}_n=-\arccos \frac{\left|F_n\right|}{2\left|S_n\right|\sqrt{\mathrm{R\&alpha;}(1-\mathrm{\&alpha;})}}-{\mathrm{\&psi;}}_n---\left(2\right)$

(n＝0，±1，±2，±3…)

7. according to the method for work of the said a kind of shaping of light pulse device based on two array fibre gratings of claim 4, it is characterized in that the amplitude of each spectral line composition of the amplitude controller output in the said step (2-3) | F _n| be amplitude by each bar spectral line of input optical frequency com | S _n|, initial phase ψ _n, coupling mechanism splitting ratio α: the phase shift of the reflectivity R of 1-α, Fiber Bragg Grating FBG, each bar spectral line of two paths of signals

And θ _nCommon decision, the phase place P of each spectral line composition of amplitude controller output _nBe initial phase ψ by each bar spectral line of input optical frequency com _nAnd the Fiber Bragg Grating FBG array is to the phase shift of each bar spectral line generation of two paths of signals

And θ _nCommon decision, the phase place of each spectral line composition of amplitude controller output equals the integral multiple of 2 π, and is as follows:

(n=0, ± 1, ± 2, ± 3 ...), m is an integer.

8. according to the method for work of claim 4 or 6 said a kind of shaping of light pulse devices based on two array fibre gratings, it is characterized in that the light pulse of said even function waveform is the even function waveform light pulse of periodically Gauss light pulse, periodically triangle light pulse, periodically bilateral index light pulse, periodically all-wave cosine light pulse, periodically half-wave cosine light pulse, repetition frequency multiplication or the even function waveform light pulse that the adjacent pulse amplitude can independently be controlled.

9. according to the method for work of the said a kind of shaping of light pulse device based on two array fibre gratings of claim 4; It is characterized in that the interference of two paths of signals in coupling mechanism in the said step (2-3) makes the spectral line of output spectrum be spaced apart the spectral line twice at interval of input optical frequency com, the then even function waveform light pulse of the port D of coupling mechanism output repetition frequency multiplication.

10. according to the method for work of the said a kind of shaping of light pulse device based on two array fibre gratings of claim 4; It is characterized in that the interference of two paths of signals in coupling mechanism in the said step (2-3) makes have two groups of spectral lines at interval to satisfy the amplitude of the Fourier coefficient of the different even function waveform light pulse of peak value respectively in the output spectrum, the then even function waveform light pulse that can independently control of the port D of coupling mechanism output adjacent pulse amplitude.

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