弱非周期性相位取样啁啾光栅的优化方法  

Optimization of Weakly Aperiodic Phase-Only Sampled Chirp Gratings

作　　者：黄力群[1] 黄卫平 陈根祥 王里[1] 

机构地区：[1]北京交通大学光波技术研究所,北京100044 [2]Electrical and Computer Engineering Dept. McMaster Univ.CA

出　　处：《中国激光》2004年第9期1099-1102,共4页Chinese Journal of Lasers

摘　　要：取样光栅可以同时对多个信道进行滤波或色散补偿 ,所以在波分复用 (WDM)系统中有广泛的应用 ,其中周期相位取样光栅是一种很有前途的设计方法 ,但周期取样的方法会使取样光栅的所有信道具有相同的色散补偿能力。提出设计弱非周期性相位取样啁啾光栅的优化方法 ,通过引入一组与信道色散补偿量有关的啁啾控制参数 ,可使不同信道的色散补偿量存在差异。运用该方法设计出弱非周期的取样光栅后 ,可用传输矩阵法来模拟该光栅的复反射谱 ,结果显示通过调整啁啾控制参数 ,可方便地控制不同信道的色散补偿能力 ,从而能实现对光纤链路色散与色散斜率的同时补偿 ,而且取样函数的幅度值的起伏则被完全消除。Sampled fiber Bragg gratings (FBG) have many applications in wavelength division multiplexed (WDM) systems, and can be filtering or chromatic dispersion compensating simultaneously in multiple channels. Periodic phase-only sampling is a preferable approach to the design of multi-channel FBG, which facilitates the fabrication of multi-channel FBG. However the periodic sampling function replicates a given chromatic dispersion function, as a result, all the channels are identical and the resulting device cannot compensate for the dispersion slope. An optimization method is presented to design weakly aperiodic phase-only sampled gratings, and a set of chirp controlling parameters, which are related to chromatic dispersion in each channel, are introduced to compensate the chromatic dispersion and the dispersion slope simultaneously. By using the simulated annealing method, an optimized set of the relative channel phases can be found to reducing the difference between the minimum and the maximum values of the amplitude modulation of the sampling function. Then, an iterative procedure, called the Gerchberg-Saxton algorithm, is applied to remove the amplitude modulation of the sampling function, and the aperiodic phase-only sampled grating is synthesized successfully. Finally, the complex reflection spectrum of the aperiodic phase-only sampled grating is simulated by using the transfer matrix method. All time delay curves in all channels are overlapped in one figure for a visible comparison of their slope, and the result shows that the dispersion compensation capacity in each channel can match with the dispersion slope of fiber link exactly. However, as a price of the Gerchberg-Saxton algorithm, the additional channels appear at both sides of the reflection spectrum.

关 键 词：光电子学 取样啁啾光栅 色散补偿 多信道 弱非周期性 

分 类 号：TN929.11[电子电信—通信与信息系统]