同谱段异频点高稳定四路集成激光器模块

High Stability Four-lane Integrated Laser Module with Different Frequency in the Same Spectrum

面向高速空间相干光通信的应用需求,研制了一种同谱段异频点高稳定的四路集成激光器模块,并采用了梯度反馈控制方法,该反馈方法根据温度反馈值将控制事件分为五种层级,按照优先级顺序梯次调控每路温度和电流,降低了温度漂移和电流抖动,从而有效降低了伺服系统对激光器线宽的影响.将该方法应用到模块控制中,为了给它提供更加精确的温度反馈值,在硬件方面采用温度被动反馈放大电路,消除了电流分量引起的误差,实验测得温度漂移低于0.001℃,电流抖动低于0.6μA.采用外腔半导体激光器,集成为模块后四路激光器洛伦兹线宽在4.5~7.5kHz之间,阿伦方差均小于4×10^(-9).将该激光器模块应用到空间光通信中,测试了四种调制格式下的误码率,并演示验证了4×50Gb/s16QAM超高速空间相干光通信,结果表明该模块在空间光通信中具有良好的应用前景.

In order to satisfy the application requirements of high-speed free-space coherent optical communication,the high stability four-lane integrated laser module with different frequency in the same spectrum was fabricated.The method of the gradient feedback control was proposed and it distinguish control cases with five levels which were set by the feedback values of temperature.The current and temperature of each lane are controlled step by step based on the priority order in this method and thatwill reduce the temperature drift,the current jitter and the influence of servo system on the linewidth of lasers.This method was applied to the module and it needed the more accurate feedback values of the temperature.Hence,the passive feedback amplifying circuit of the temperature was adopted and it can eliminate the deviation caused by the current component.The temperature drift and the current jitter which were less than 0.001 ℃ and 0.6μA,respectively,were tested.After being integrated into the module,the Lorentzian linewidth of four external cavity diode lasers were 4.5-7.5 kHz and the Allan variances were all less than 4×10^（-9）.In the Free-Space Optical（FSO）communication,the bit error rates of four modulation formats were tested with four lasers in the module and the ultra-high speed free-space coherent optical communication with 4×50 Gb/s 16 QAM was demonstrated.The experimental results show that the four-lane integrated module has a wide application prospect in the FSO communication.