CN103278998A - Fiber parameter amplification system for improving energy conversion efficiency of pump light to signal light - Google Patents

Abstract

The invention discloses an optical fiber parametric amplification system for improving the energy conversion efficiency of pump light to signal light, which consists of signal laser, pump laser, polarization controller, phase modulator, optical attenuator, erbium-doped fiber amplifier, pseudo-random sequence , an optical coupler, a highly nonlinear optical fiber, a fiber Bragg grating and a spectrum analyzer, and is characterized in that a fiber Bragg grating is connected between highly nonlinear optical fibers, and the fiber Bragg grating is used to reflect part of the idler light to change the fiber parameter during the amplification process The phase mismatch of the optical fiber parametric amplification system improves the energy conversion efficiency of pump light to signal light. The present invention improves the energy conversion efficiency of the pump light to the signal light of the single-pump fiber parametric amplification system and improves the gain of the system by adopting the cascading mode of the fiber Bragg grating and the highly nonlinear fiber, which is beneficial to the all-optical network. The development of all-optical amplification technology.

Description

A Fiber Parametric Amplification System for Improving the Energy Conversion Efficiency of Pumping Light to Signal Light

technical field

The present invention relates to a single-pump optical fiber parametric amplification system, in particular to a single-pump optical fiber parametric amplification system which adopts fiber Bragg grating and highly nonlinear optical fiber cascading to realize the improvement of pump light to signal light energy conversion efficiency, and is suitable for In the field of fiber optic communication and nonlinear fiber optics.

Background technique

With the rapid development of Internet broadband services, the traffic has shown explosive growth. Because of its large capacity, broadband, low loss and anti-electromagnetic interference, the optical fiber communication system constitutes the backbone of modern communication networks. Among them, the wavelength division multiplexing technology can make full use of the transmission bandwidth of the optical fiber, and is the preferred solution for backbone network configuration; however, the wavelength division multiplexing system is also accompanied by problems such as loss in data transmission, so advanced all-optical Magnification technology as support. Among them, the optical fiber parametric amplification technology has significant advantages such as the ability to amplify signals of any wavelength, low noise figure, broadband, high gain, high phase sensitivity, and idle frequency band generation, and has received more and more attention. Improving the gain characteristics of the amplification system is an important index for studying the amplification system, and the energy conversion efficiency from pump light to signal light in the fiber parametric amplification system is the decisive factor affecting the system gain. Therefore, how to improve the efficiency of energy conversion from pump light to signal light in the optical fiber parametric amplification system has become a key factor in the study of optical amplification systems.

As far as the current research progress is concerned, it is mainly through the use of optical fibers with high nonlinear coefficients, increasing the input power of pump light, connecting optical isolators between two sections of highly nonlinear optical fibers to suppress stimulated Brillouin scattering, and using Dispersion compensation is realized by cascading dispersion compensation fibers between highly nonlinear fibers to improve the energy conversion efficiency of pump light to signal light in the fiber parametric amplification system.

Contents of the invention

On the basis of the prior art, the present invention proposes a single-pump optical fiber parametric amplification system that uses fiber Bragg gratings and highly nonlinear optical fiber cascades to improve the energy conversion efficiency from pump light to signal light. Fiber Bragg gratings are connected between nonlinear fibers to reflect part of the idler light generated after passing through the first highly nonlinear fiber, to compensate the phase mismatch in the process of fiber parametric amplification, and to realize the pump light direction signal of the single-pump fiber parametric amplification system Improvement of light energy conversion efficiency.

In order to solve the above technical problems, the present invention provides the following technical devices:

A fiber parametric amplification system for improving the energy conversion efficiency of pump light to signal light, comprising a signal laser, a first polarization controller, an optical attenuator, a pump laser, a second polarization controller, a phase modulator, a 1Gb/s pseudo A random sequence, a third polarization controller, an erbium-doped fiber amplifier, an optical coupler, a first highly nonlinear optical fiber, a fiber Bragg grating, a second highly nonlinear optical fiber, and a spectrum analyzer are composed; the details are as follows: for generating signal light The signal laser is connected to the first polarization controller used to adjust the polarization state of the signal light, and then connected to the optical attenuator used to adjust the signal light power; the other way, the pump laser used to generate pump light is connected to adjust The second polarization controller of the polarization state of the pump light is then connected to the phase modulator (wherein the phase modulator is connected to a 1Gb/s pseudo-random sequence) for suppressing part of the stimulated Brillouin scattering, and then the phase modulator is connected to the third On the polarization controller and the erbium-doped fiber amplifier used to amplify the power of the pump light, then the two adjusted signal light and pump light are coupled into the first high nonlinear fiber through the optical coupler, and then connected to the fiber Bragg On the grating, part of the idler light is reflected by the fiber Bragg grating to compensate for the phase mismatch in the process of fiber parametric amplification, and then connected to the second high nonlinear fiber to realize the improvement of the energy conversion efficiency of the pump light to the signal light and the improvement of the signal light energy conversion efficiency. Further amplification, and then the change of the optical power of the system is analyzed by the spectrum analyzer.

After the above design, fiber Bragg gratings are connected between highly nonlinear fibers to reflect part of the idler light generated after passing through the first highly nonlinear fiber, and change the pumping light and signal after passing through the first highly nonlinear fiber. The relative power between light, idler light and second-order sideband light compensates for the phase mismatch in the fiber parametric amplification process, thereby improving the energy conversion efficiency from pump light to signal light in the fiber parametric amplification system.

The invention has the following advantages: between two sections of highly nonlinear optical fibers, the scheme of cascading uniform fiber Bragg gratings and highly nonlinear optical fibers is used to compensate the phase mismatch of the optical fiber parametric process, effectively improving the pumping power of the optical fiber parametric amplification system. The conversion efficiency of the light energy to the signal is easy to realize in the present invention, and the characteristics of the optical fiber parameter amplification system are improved.

Description of drawings

Fig. 1 is a system block diagram of the present invention.

Fig. 2 is a schematic diagram of cascaded four-wave mixing effect.

Fig. 3 is (a) the system optical power spectrum diagram of the output after passing through the first highly nonlinear optical fiber; (b) the system optical power spectrum diagram output after passing through the first highly nonlinear optical fiber and the second highly nonlinear optical fiber; (c ) System optical power spectrum output after passing through the first highly nonlinear fiber and fiber Bragg grating; (d) System optical power spectrum output after passing through the first highly nonlinear fiber, fiber Bragg grating and second highly nonlinear fiber.

FIG. 4 is a diagram showing the influence of the input signal optical power on the output signal optical power.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the system of the present invention consists of a signal laser, a first polarization controller, an optical attenuator, a pump laser, a second polarization controller, a phase modulator, a 1Gb/s pseudo-random sequence, a third polarization controller, It consists of an optical coupler, a first highly nonlinear fiber, a fiber Bragg grating, a second highly nonlinear fiber and a spectrum analyzer.

The signal laser can generate signal light with a wavelength of 1563.5nm, and the pump laser can generate pump light with a wavelength of 1556.8nm. The signal light generated by the signal laser enters the optical attenuator after adjusting its polarization state by the first polarization controller. The power is adjusted to -19.64dBm; the pump light generated by the pump laser is adjusted to its polarization state by the second polarization controller, and then enters the phase modulator driven by a 1Gb/s pseudo-random sequence and the first phase modulator for further adjusting its polarization state. After the three polarization controllers enter the erbium-doped fiber amplifier to amplify the power of the pumping light to 25dBm, then the signal light and pumping light are coupled into the 10dB optical coupler, the fiber length is 1000m, the zero dispersion wavelength λ ₀ =1556nm, high nonlinearity Coefficient γ=30W ^-1 km ^-1 , dispersion slope 0.02ps/nm ² /km produces parametric amplification process in the first highly nonlinear fiber, amplifies signal light and generates idler light and second-order sideband light. The schematic diagram of the cascaded four-wave mixing effect is shown in Figure 2. During the fiber parametric amplification process, the angular frequency ω ₁ of the pump light, the angular frequency ω ₂ of the signal light, and the angular frequency ω ₃ of the idler light satisfy 2ω ₁ =ω ₂ +ω ₃ , the signal light and the idler light are called the first-order sideband light, and under certain conditions, the pump light can interact with the signal light and the idler light to generate the second-order sideband light, and the second-order sideband light The angular frequencies of the sideband light satisfy ω ₄ =2ω ₂ −ω ₁ and ω ₅ =2ω ₃ −ω ₁ respectively.

The optical power spectrum output through the first highly nonlinear optical fiber is shown in Figure 3(a). It can be seen that the pump light with an input power of 25dBm and the signal light with an input power of -19.64dBm enter the first through a 10dB coupler After a highly nonlinear fiber, the idler light and the second-order sideband light are generated through the fiber parametric amplification process, the signal light power is increased to -8.98dBm, the pump light power is reduced to 15.73dBm, and the average of the generated second-order sideband light The power is about -35dBm, corresponding to a power difference of 25.91dB between the pump light and the signal light. When cascading with fiber Bragg gratings is not used, the second highly nonlinear fiber is directly connected after the first highly nonlinear fiber, and the optical power spectrum is measured as shown in Figure 3(b). It can be seen that the first high nonlinear fiber is directly connected The power of the second-order sideband light after the second-high nonlinear fiber is increased to about -20dBm, corresponding to more optical power transferred to the second-order sideband, while the power of the signal light is reduced to -14.63dBm instead, and the pump light The power difference between the signal light and the signal light is 24.71dB; and after the fiber Bragg grating is cascaded in the first highly nonlinear fiber, the optical power spectrum shown in Figure 3(c) is obtained, and the power of the idler light in the figure changes from - 8.93dBm is reduced to -15.91dBm, and the signal optical power is slightly reduced to -9.06dBm due to the factor of connection loss; then the second highest nonlinear fiber is connected after the fiber Bragg grating, and the power spectrum shown in Figure 3(d) is obtained, It can be seen that the power of the signal light increases to -5.39dBm, the power of the pump light decreases to 11.89dBm, and the power difference between the pump light and the signal light is 17.28dB. It can be seen from the results in Fig. 3 that after using fiber Bragg gratings to cascade between two sections of highly nonlinear fibers, the power of signal light is increased, and the energy conversion efficiency of pump light to signal light is also significantly improved.

Further, change the input signal optical power, and analyze the influence of fiber Bragg gratings on the output signal optical power of the system before and after cascading between highly nonlinear fibers. As shown in Figure 4, the input signal optical power is between -24dBm to - When changing between 20.5dBm, the output signal light power is increased by 10dB on average after adopting the fiber Bragg grating, which means that the energy conversion efficiency of pump light to signal light has been significantly improved.

In the optical fiber parametric amplification system of the present invention, the improvement of the energy conversion efficiency from pump light to signal light depends on the nonlinear coefficient of the highly nonlinear optical fiber, the length of the fiber, the dispersion characteristics, the input power, wavelength, and polarization state of the pump light and signal light. , the reflection coefficient of the fiber Bragg grating and the Bragg wavelength and other factors, properly adjusting these parameters can further improve the characteristics of the fiber parametric amplification system, and promote the application and development of the fiber parametric amplification technology in the fiber optic communication system.

Claims (3)

1. An optical fiber parametric amplification system that improves the energy conversion efficiency of pump light to signal light, comprising a signal laser, a first polarization controller, an optical attenuator, a pump laser, a second polarization controller, a phase modulator, a 1Gb/ s pseudo-random sequence, a third polarization controller, an erbium-doped fiber amplifier, an optical coupler, a first highly nonlinear optical fiber, a fiber Bragg grating, a second highly nonlinear optical fiber and a spectrum analyzer, are characterized in that they are used to generate signals The optical signal laser is connected to the first polarization controller, the first polarization controller is connected to the optical attenuator, the pump laser for generating pump light is connected to the second polarization controller, the second polarization controller and The 1Gb/s pseudo-random sequence is connected to the phase modulator, the phase modulator is connected to the third polarization controller, the third polarization controller is connected to the erbium-doped fiber amplifier, and the two adjusted signal light and pump light pass through The optical coupler is coupled to the first highly nonlinear fiber, the first highly nonlinear fiber is connected to the fiber Bragg grating, the fiber Bragg grating is connected to the second highly nonlinear fiber, and the output of the second highly nonlinear fiber is connected to the spectrum Analyzer. 2. A fiber parametric amplification system for improving the energy conversion efficiency of pump light to signal light according to claim 1, its additional technical feature is: connecting the fiber Bragg grating to the first high nonlinear optical fiber and the second high nonlinear optical fiber Between the nonlinear fibers, the fiber Bragg grating is used to reflect part of the idler light to compensate the phase mismatch in the process of fiber parameters, so as to improve the energy conversion efficiency of pump light to signal light. 3. An optical fiber parametric amplification system for improving energy conversion efficiency from pump light to signal light according to claim 1, its additional technical feature is: said input signal light power is between -24dBm to -20.5dBm .

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