窄线宽、大调谐带宽的本振激光种子源是空间相干光通信系统中的核心组件之一,通过窄线宽种子源结合外电光调制和窄带光栅滤波的方案,可以实现窄线宽和大调谐带宽,但通过温度控制的光纤光栅难以适应空间动平台间存在的高速多普勒频移。采用压电陶瓷控制的光纤光栅,结合梯度下降算法的闭环系统,实现了光纤光栅和注入激光波长的相对锁定。所提方案可适应40 MHz/s以上的空间多普勒频移。

A local oscillation laser seed source with narrow linewidth and large tuning bandwidth is one of the core components of space coherent optical communication systems. Using the narrow linewidth seed source in combination with external electro-optical modulation and narrowband grating filtering, narrow line width and high tuning bandwidth can be achieved, but the fiber Bragg grating controlled by temperature is difficult to adapt to the high-speed Doppler frequency shift between moving platforms. In this paper, a closed-loop system of a fiber Bragg grating controlled by piezoelectric ceramics in combination with the gradient descent algorithm is used to realize the relative locking of the fiber grating and the injected laser wavelength. The proposed scheme can adapt to spatial Doppler shift above 40 MHz/s.