CN202854463U

CN202854463U - Single pumping light fiber parametric amplifier capable of filtering idler frequency light and achieving gain optimization

Info

Publication number: CN202854463U
Application number: CN 201220338169
Authority: CN
Inventors: 朱宏娜; 罗斌; 赵建朋; 潘悦梅; 项水英; 常相辉
Original assignee: Southwest Jiaotong University
Current assignee: Southwest Jiaotong University
Priority date: 2012-07-13
Filing date: 2012-07-13
Publication date: 2013-04-03
Anticipated expiration: 2022-07-13

Abstract

The utility model discloses a single-pump optical fiber parametric amplifier for filtering idler light to realize gain optimization, which is composed of a signal laser, a pump laser, a polarization controller, an optical coupler, an optical filter and a high nonlinear optical fiber. It is to introduce an optical filter between two sections of highly nonlinear optical fibers to filter the idler light, compensate the phase mismatch in the fiber parametric process, and then improve the peak gain of the fiber parametric amplifier and broaden and flatten the gain bandwidth of the fiber parametric amplifier. . The utility model filters the idler light by introducing an optical filter, thereby optimizing the gain characteristic of the single-pump optical fiber parametric amplifier, which is beneficial to the development of the all-optical amplification technology in the optical fiber communication system.

Description

Gain-optimized single-pump fiber parametric amplifier for filtering idler light

技术领域 technical field

本实用新型涉及一种单泵浦光纤参量放大器，尤其是一种采用光滤波器过滤闲频光实现增益优化的单泵浦光纤参量放大器，适用于光纤通信和非线性光纤光学领域。 The utility model relates to a single-pump optical fiber parametric amplifier, in particular to a single-pump optical fiber parametric amplifier which adopts an optical filter to filter idler light to realize gain optimization, and is suitable for the fields of optical fiber communication and nonlinear optical fiber optics. the

背景技术 Background technique

随着光纤通信系统的发展，密集波分复用技术因其可大量增加光纤的传输容量的特性，实现了高速和超高速的数据传输，但是也伴随数据传输的衰减问题，所以光放大器是波分复用光纤传输系统的关键。其中，直接对光信号进行放大的全光放大器能够同时对多个波长进行放大，是光放大器研究发展的趋势。而利用四波混频效应进行信号放大的光纤参量放大器能在任意波长处提供宽带的平坦高增益，是近年来新的研究热点。优化放大器的增益特性是研究放大器的重要指标，因此，如何优化光纤参量放大器的增益特性成为研究光放大器的重要目标。 With the development of optical fiber communication systems, dense wavelength division multiplexing technology has realized high-speed and ultra-high-speed data transmission due to its ability to greatly increase the transmission capacity of optical fibers, but it is also accompanied by the attenuation problem of data transmission, so optical amplifiers are wave The key to division multiplexing optical fiber transmission system. Among them, the all-optical amplifier that directly amplifies optical signals can simultaneously amplify multiple wavelengths, which is the development trend of optical amplifier research. The fiber parametric amplifier, which utilizes the four-wave mixing effect to amplify signals, can provide broadband flat high gain at any wavelength, and is a new research hotspot in recent years. Optimizing the gain characteristics of an amplifier is an important index for researching an amplifier. Therefore, how to optimize the gain characteristics of an optical fiber parametric amplifier has become an important goal of researching an optical amplifier. the

对于光纤参量放大器增益的优化方法，目前主要有采用双泵浦结构、采用几段零色散波长不同的高非线性光纤级联、提高泵浦光输入功率和增加高非线性光纤非线性系数等方式。 For the optimization method of the fiber parametric amplifier gain, there are mainly methods such as adopting a double pump structure, adopting several highly nonlinear optical fiber cascades with different zero-dispersion wavelengths, increasing the input power of the pump light, and increasing the nonlinear coefficient of the highly nonlinear optical fiber. . the

实用新型内容 Utility model content

本实用新型在于对现有技术的不足，提出一种采用光滤波器过滤闲频光实现增益优化的单泵浦光纤参量放大器系统，在两段除了光纤长度不同而其余光纤参数都相同的高非线性光纤之间插入光滤波器对闲频光进行滤波，实现单泵浦光纤参量放大器增益的优化。 The utility model aims at addressing the deficiencies of the prior art, and proposes a single-pump optical fiber parametric amplifier system that uses an optical filter to filter idler light to achieve gain optimization. In the two sections, except for the difference in the length of the optical fiber, other optical fiber parameters are the same at high An optical filter is inserted between the nonlinear optical fibers to filter the idler light to realize the optimization of the gain of the single-pumped optical fiber parametric amplifier. the

本实用新型的目的是通过如下手段来实现的。 The purpose of this utility model is achieved by the following means. the

过滤闲频光实现增益优化的单泵浦光纤参量放大器，由信号激光器、泵浦激光器、偏振控制器、光耦合器、光滤波器和高非线性光纤构成；包含如下的处理步骤：信号激光器产生的信号光和泵浦激光器产生的泵浦光分别经第一偏振控制器和第二偏振控制器调整其偏振态后，经光耦合器耦合进入第一高非线性光纤，通过高非线性光纤中的参量过程实现闲频光的产生和信号光的放大，接着连接到光滤波器，通过光滤波器对闲频光进行滤波后，再进入第二高非线性光纤，实现对信号光的再放大。本实用新型采用光滤波器对闲频光进行滤波，实现了单泵浦光纤参量放大器增益的优化。 A single-pump fiber parametric amplifier that filters idler light to achieve gain optimization. It is composed of a signal laser, a pump laser, a polarization controller, an optical coupler, an optical filter, and a highly nonlinear optical fiber; it includes the following processing steps: signal laser generation The signal light of the signal light and the pump light generated by the pump laser are respectively adjusted to the polarization state by the first polarization controller and the second polarization controller, and then coupled into the first high nonlinear fiber by the optical coupler, and passed through the high nonlinear fiber The parametric process realizes the generation of idler light and the amplification of signal light, and then connects to an optical filter. After filtering the idler light through the optical filter, it enters the second high nonlinear optical fiber to realize the re-amplification of signal light. . The utility model adopts an optical filter to filter the idle frequency light, and realizes the optimization of the gain of the single-pump optical fiber parametric amplifier. the

经过如上的设计，在两段高非线性光纤之间采用一个光滤波器过滤闲频光，减少了闲频光的功率，从而调整了泵浦光、信号光和闲频光之间的相对相位关系，进而补偿了第一段光纤参量过程中的相位失配，提高了光纤参量放大器的峰值增益并拓展和平坦化了光纤参量放大器的增益带宽。本实用新型具有如下优点：在两段高非线性光纤除了光纤长度不同而其余光纤参数都相同的条件下，首次采用光滤波器过滤闲频光的方案补偿光纤参量过程的相位失配，有效地优化了光纤参量放大器的增益，本实用新型结构简单容易实现，优化了光纤参量放大器的增益特性和系统灵活性。 After the above design, an optical filter is used to filter the idler light between two sections of highly nonlinear optical fibers, reducing the power of the idler light, thereby adjusting the relative phase between the pump light, signal light and idler light Relationship, and then compensate the phase mismatch in the first section of fiber parametric process, improve the peak gain of the fiber parametric amplifier and expand and flatten the gain bandwidth of the fiber parametric amplifier. The utility model has the following advantages: under the condition that the two sections of highly nonlinear optical fibers are different except for the length of the optical fiber and the other optical fiber parameters are the same, for the first time, the optical filter is used to filter the idler light to compensate the phase mismatch of the optical fiber parameter process, effectively The gain of the optical fiber parametric amplifier is optimized, the utility model has a simple structure and is easy to realize, and the gain characteristic and system flexibility of the optical fiber parametric amplifier are optimized. the

附图说明： Description of drawings:

图1为本实用新型的系统框图。 Fig. 1 is a system block diagram of the utility model. the

图2为泵浦光功率、闲频光功率、sinθ和信号光功率随光纤长度变化的示意图，其中实线为采用光滤波器的，点线为没有采用光滤波器的。 Figure 2 is a schematic diagram of the pump optical power, idler optical power, sinθ and signal optical power changing with the length of the optical fiber, where the solid line is for the optical filter used, and the dotted line is for the optical filter not used. the

图3为泵浦光向信号光的能量转换效率随光纤长度变化的关系示意图，其中实线为采用光滤波器的，点线为没有采用光滤波器的。 Fig. 3 is a schematic diagram of the relationship between the energy conversion efficiency of the pump light to the signal light as a function of the length of the optical fiber, wherein the solid line indicates the optical filter is used, and the dotted line indicates the optical filter is not used. the

图4为信号光增益随信号光波长变化的关系示意图，其中实线为采用光滤波器的，点线为没有采用光滤波器的。 FIG. 4 is a schematic diagram of the relationship between the gain of signal light and the wavelength of the signal light, wherein the solid line indicates the use of an optical filter, and the dotted line indicates the use of an optical filter. the

具体实施方式Detailed ways

下面结合附图对本实用新型的实施做进一步的描述。 The implementation of the utility model will be further described below in conjunction with the accompanying drawings. the

如图1所示，本实用新型系统由信号激光器、泵浦激光器、第一偏振控制器、第二偏振控制器、光耦合器、第一高非线性光纤、光滤波器和第二高非线性光纤构成。 As shown in Figure 1, the utility model system consists of a signal laser, a pump laser, a first polarization controller, a second polarization controller, an optical coupler, a first highly nonlinear optical fiber, an optical filter and a second highly nonlinear Optical fiber composition. the

在图1中，信号激光器产生的波长为1588nm的信号光，与泵浦激光器产生的波长为1560nm的泵浦光，分别经过第一偏振控制器和第二偏振控制器调整其偏振态后耦合进入光耦合器，在光纤长度为160m，零色散波长为1556nm，高非线性系数为20W^-1Km^-1，色散斜率为0.03ps/nm²/Km的第一高非线性光纤中产生参量放大过程，产生闲频光并放大信号光。在光纤参量放大过程中泵浦光、信号光和闲频光间的角频率满足2ω_p＝ω_s+ω_i的条件。在各个光波偏振态为线偏振且为连续光的情况下，三个光波间的光功率和相对相位差满足下面的方程： In Figure 1, the signal light with a wavelength of 1588nm generated by the signal laser and the pump light with a wavelength of 1560nm generated by the pump laser are coupled into the The optical coupler produces a parametric amplification process in the first high nonlinear fiber with a fiber length of 160m, a zero dispersion wavelength of 1556nm, a high nonlinear coefficient of 20W ^-1 Km ^-1 , and a dispersion slope of 0.03ps/nm ² /Km , generating idler light and amplifying signal light. The angular frequencies among pump light, signal light and idler light satisfy the condition of 2ω _p =ω _s +ω _i in the process of fiber parametric amplification. When the polarization state of each light wave is linearly polarized and continuous light, the optical power and relative phase difference between the three light waves satisfy the following equation:

$\frac{{dP dP}_{p p}}{dz dz} = = - - 44 γ γ {(({P P}_{p p}^{22} {P P}_{s the s} {P P}_{i i}))}^{11 / / 22} sin sin θ θ - - - - - - ((11))$

$\frac{{dP dP}_{s the s}}{dz dz} = = 22 γ γ {(({P P}_{p p}^{22} {P P}_{s the s} {P P}_{i i}))}^{11 / / 22} sin sin θ θ - - - - - - ((22))$

$\frac{{dP dP}_{i i}}{dz dz} = = 22 γ γ {(({P P}_{p p}^{22} {P P}_{s the s} {P P}_{i i}))}^{11 / / 22} sin sin θ θ - - - - - - ((33))$

$\frac{dθ dθ}{dz dz} = = Δβ Δβ + + γ γ (({22 P P}_{p p} - - {P P}_{s the s} - - {P P}_{i i})) + + γ γ [[{(({P P}_{p p}^{22} {P P}_{s the s} / / {P P}_{i i}))}^{11 / / 22} + + {(({P P}_{p p}^{22} {P P}_{i i} / / {P P}_{s the s}))}^{11 / / 22} - - 44 {(({P P}_{s the s} {P P}_{i i}))}^{11 / / 22}]] cos cos θ θ - - - - - - ((44))$

其中P_p，P_s和P_i分别是泵浦光、信号光和闲频光的光功率，γ是高非线性光纤的非线性系数，Δβ为线性波矢失配系数且Δβ＝β_s+β_i-2β_p。θ(z)是三个光波间的相对相位差，为： where P _p , P _s and P _i are the optical power of pump light, signal light and idler light respectively, γ is the nonlinear coefficient of highly nonlinear fiber, Δβ is the linear wave vector mismatch coefficient and Δβ=β _s + β _i -2β _p . θ(z) is the relative phase difference between the three light waves, which is:

θ(z)＝Δβz+φ_s(z)+φ_i(z)-2φ_p(z) (5) θ(z)＝Δβz+φ _s (z)+φ _i (z)-2φ _p (z) (5)

其中φ_p，s，i(z)为每个光波的相位。由公式(1)-(3)可以看出，如果sinθ＞0，意味着能量从泵浦光向信号光和闲频光转移，但是如果sinθ＜0，能量从信号光和闲频光向泵浦光转移。 where φ _{p, s, i} (z) is the phase of each light wave. It can be seen from formulas (1)-(3) that if sinθ>0, it means that energy is transferred from pump light to signal light and idler light, but if sinθ<0, energy is transferred from signal light and idler light to pump light Pu light transfer.

接着在第一高非线性光纤输出端连接一个光滤波器，光滤波器过滤闲频光后，补偿了光纤参量过程的相位失配。然后通过长度为43m的第二高非线性光纤继续对信号光进行参量放大，实现信号光功率的进一步提高。其中第二高非线性光纤与第一高非线性光纤除了光纤长度不同外，其余光纤参数性质都一致。图2说明了是否采用光滤波器过滤闲频光时(1)泵浦光、(2)闲频光、(3)sinθ和(4)信号光的功率随高非线性光纤长度变化的关系。可以看出输入功率为1.8W的泵浦光和输入功率为0.1mW的信号光经过第一高非线性光纤后，通过光纤参量放大过程产生闲频光，并且泵浦光的能量向信号光和闲频光转移，在光纤长度160m处泵浦光的功率最低减少至0.79W，信号光的功率最大放大到0.505W，如果没有光滤波器的引入，随着光纤长度的增加，信号光的功率反而会继续减少。当引入了光滤波器后，在光纤长度160m处，因为光滤波器对闲频光的滤波作用，如图2(2)中实线所示闲频光的功率从0.505W减少到接近于0。同时如图2(3)所示，没有采用光滤波器时，sinθ的取值在160m后从正值变成了负值，负值代表能量转换方向从信号光和闲频光转向泵浦光；而采用滤波器后，sinθ的取值在整个光纤长度内都是正值，也即是信号光的功率一直在增加的。接着如图2(4)中实线所示，光滤波器的采用使信号光的功率从0.505W进一步提高到0.595W。简言之，通过光滤波器对闲频光滤波提高了信号光的功率，亦是提高了光纤参量放大器的增益。并且，通过光滤波器的引入，泵浦光向信号光的能量转换效率也明显提高了，定义泵浦光向信号光的能量转换效率为： Then an optical filter is connected to the output end of the first highly nonlinear optical fiber, and the optical filter compensates the phase mismatch of the optical fiber parametric process after filtering the idler light. Then, the signal light is continuously parametrically amplified through the second highly nonlinear optical fiber with a length of 43 m, so as to further increase the power of the signal light. Wherein the second highly nonlinear optical fiber is identical to the first highly nonlinear optical fiber except for the length of the optical fiber, and the properties of other optical fiber parameters are the same. Figure 2 illustrates the relationship between the power of (1) pump light, (2) idler light, (3) sinθ and (4) signal light as a function of the length of the highly nonlinear fiber when optical filters are used to filter the idler light. It can be seen that after the pump light with an input power of 1.8W and the signal light with an input power of 0.1mW pass through the first highly nonlinear optical fiber, idler light is generated through the fiber parametric amplification process, and the energy of the pump light is transferred to the signal light and Idler light transfer, the minimum power of the pump light is reduced to 0.79W at the fiber length of 160m, and the maximum power of the signal light is amplified to 0.505W. If there is no introduction of optical filters, as the fiber length increases, the power of the signal light Instead, it will continue to decrease. When the optical filter is introduced, at the fiber length of 160m, because of the filtering effect of the optical filter on the idler light, as shown by the solid line in Figure 2(2), the power of the idler light decreases from 0.505W to close to 0 . At the same time, as shown in Figure 2(3), when no optical filter is used, the value of sinθ changes from a positive value to a negative value after 160m, and a negative value indicates that the direction of energy conversion is from signal light and idler light to pump light ; After using the filter, the value of sinθ is positive throughout the length of the fiber, that is, the power of the signal light is always increasing. Next, as shown by the solid line in Fig. 2(4), the use of the optical filter further increases the power of the signal light from 0.505W to 0.595W. In short, filtering the idler light through the optical filter increases the power of the signal light and also increases the gain of the fiber parametric amplifier. Moreover, through the introduction of optical filters, the energy conversion efficiency of pump light to signal light is also significantly improved. The energy conversion efficiency of pump light to signal light is defined as:

${η η}_{pump the pump - - signal signal} = = \frac{{P P}_{s the s} ((z z)) - - {P P}_{s the s} ((00))}{{P P}_{p p} ((00))} - - - - - - ((66))$

式中P_s(0)和P_p(0)分别是进入光纤的信号光和泵浦光的初始功率，P_s(z)是输出的信号光功率。如图3所示，加入光滤波器后，泵浦光向信号光的能量转换效率从光纤长度160米处的28％增加到203米处的了33％，而如果没有光滤波器的引入，泵浦光向信号光的能量转换效率会从28％减少到5％。即在输出端，总的能量转换效率提高了28％。 where P _s (0) and P _p (0) are the initial powers of the signal light and pump light entering the fiber respectively, and P _s (z) is the output signal light power. As shown in Figure 3, after adding an optical filter, the energy conversion efficiency of pump light to signal light increases from 28% at a fiber length of 160 meters to 33% at a fiber length of 203 meters, and if there is no introduction of an optical filter, The energy conversion efficiency of pump light to signal light will be reduced from 28% to 5%. That is, at the output, the overall energy conversion efficiency has increased by 28%.

另外，滤波器的采用不仅提高了光纤参量放大器的增益，而且拓展和平坦化了光纤参量放大器的增益带宽。如图4中实线所示，在1558nm到1598nm的波长范围内，不仅信号光的增益提高了平均8dB，并且增益带宽更加平坦和展宽了，增益带宽明显优于没有采用光滤波器的虚线所示的带宽特性。 In addition, the adoption of the filter not only improves the gain of the fiber parametric amplifier, but also expands and flattens the gain bandwidth of the fiber parametric amplifier. As shown by the solid line in Figure 4, in the wavelength range from 1558nm to 1598nm, not only the gain of the signal light is increased by an average of 8dB, but also the gain bandwidth is flatter and wider, and the gain bandwidth is obviously better than that obtained by the dotted line without an optical filter. The bandwidth characteristics shown. the

综合以上陈述，本实用新型具有如下特征：1).在光纤参量放大系统的两段高非线性光纤之间引入了光滤波器；2).利用光滤波器对闲频光进行滤波，补偿了光纤参量过程中的相位失配，优化了光纤参量放大器的增益。通过对闲频光进行滤波的系统优化了光纤参量放大器的增益特性，为全光通信系统的全光放大技术提供新的技术方案。 Based on the above statements, the utility model has the following characteristics: 1). An optical filter is introduced between two sections of high nonlinear optical fibers of the optical fiber parametric amplification system; 2). The idler light is filtered by the optical filter, compensating The phase mismatch in the fiber parametric process optimizes the gain of the fiber parametric amplifier. The gain characteristic of the fiber parametric amplifier is optimized by filtering the idler light, and a new technical solution is provided for the all-optical amplification technology of the all-optical communication system. the

以上所陈述的仅仅是本实用新型的优选实施方式，应当指出，在不脱离本实用新型实质的前提下，在实际实施中可以做出若干更改(比如改变泵浦光和信号光的输入功率和波长时，改变光滤波器的滤波效率时，改变高非线性光纤的非线性系数和光纤长度时)也应包含在本实用新型的保护范围以内。 What has been stated above is only the preferred implementation of the present utility model. It should be pointed out that without departing from the essence of the present utility model, some changes can be made in actual implementation (such as changing the input power and the input power of pump light and signal light) wavelength, when changing the filtering efficiency of the optical filter, when changing the nonlinear coefficient of the highly nonlinear optical fiber and the length of the optical fiber) should also be included in the protection scope of the present utility model. the

Claims

1. filter single pumping optical fiber parameter amplifier that ideler frequency light is realized gain optimization, by signal laser, pump laser, the first Polarization Controller, the second Polarization Controller, photo-coupler, the first highly nonlinear optical fiber, optical filter and the second highly nonlinear optical fiber form, it is characterized in that the flashlight of signal laser output and the pump light of pump laser output, adjust its polarization state through the first Polarization Controller and the second Polarization Controller respectively and be connected to the first highly nonlinear optical fiber by photo-coupler, realize the generation of ideler frequency light and the amplification of flashlight by the parametric process in the optical fiber, the output of the first highly nonlinear optical fiber is connected to optical filter, continue that by the second highly nonlinear optical fiber flashlight is carried out parameter again and amplify, realize the further optimization of flashlight gain.

2. filtration ideler frequency light according to claim 1 is realized single pumping optical fiber parameter amplifier of gain optimization, it is characterized in that, two sections except fiber lengths different but all the other optical fiber parameters all introduce optical filter between the identical highly nonlinear optical fiber ideler frequency light carried out filtering, phase mismatch in the compensated optical fiber parametric process, and then the gain characteristic of optimization optical fiber parameter amplifier.