基于相位调制和线性滤波的多信道多功能光学微分器

多功能微分器可以满足光计算和光信号处理中的多种需求, 增强灵活性. 本文从理论上推导了一种基于相位调制和线性滤波的多功能光学微分器. 并在实验中, 将传输谱线近似为线性的光纤延时干涉仪(DI)和相位调制器级联, 得到了输入信号的两种微分结果. 通过调节DI的驱动电压调节其传输谱的漂移, 当光载波位于DI的传输谱线的谷值, 则获得信号的光场微分, 当光载波位于DI传输谱的线性斜率处, 则得到输入信号的光强微分. 通过分析各种微分的平均误差, 发现DI的线性度越高, 平均误差越小. 同时基于DI传输谱线的梳状特性,证实了多信道信号的同时微分.

Multi-channel multifunctional optical differentiator based on phase modulation and linear filtering

Multifunctional photonic differentiation is robust in optical computing and optical signal processing. We theoretically propose a multifunctional optical differentiator based on phase modulation and linear filtering. We also experimentally demonstrate two kinds of differentiators by using a phase modulator cascaded a fiber delay interferometer (DI) whose transmission spectrum is approximately linear. Difference between the two differentiators relies on whether the differentiated signals are formed by the optical intensity or the optical field of the output signal, which in turn depends on the relative shift between the signal wavelength and the closest notches of a linear filter. We also show the average errors of all kinds of differentiations and results show that the increase of the degree of linearity of the transmission spectrum of the DI will reduce the average error. Moreover, we demonstrate multi-channel multifunctional differentiation due to the comb spectrum of the DI.