高功率激光器的高速率外调制技术是空间光通信发射系统中的关键技术。系统采用光纤耦合的激光器, 有效减少了传输媒质对激光功率的损耗。为了获得大功率、高速率的激光调制信号, 采用1 mm光输入口径的铌酸钽晶体电光调制器进行光强度调制, 电光调制器的调制带宽为1 GHz, 调制方式选用外调制方式。为了保证了调制器工作在线性区域, 同时降低对电光调制器的驱动电压的要求, 系统采用了自动偏置控制技术。通过加正弦波和方波信号进行调制实验, 系统实现了激光器调制速率300 Mb/s, 输出功率100 mW的指标要求。

The high-speed electro-optical modulating technology of the high-power laser is the key technology for space optical communication transmission system. This system adopts a fiber-optical coupled laser, so it has effectively decreased the spoilage of transferring medium to the laser power. In order to obtain high-power, high-speed laser modulation signal, the system adopts 1mm-diameter of the LiTaO3 electro-optical modulator. The bandwidth of the electro-optic modulator of this system is 1 GHz, and modulation type adopts the outer modulation. Moreover, in order to ensure the modulator work in the linear region and reduce the requirement to electro optical modulator drive voltage, this system uses the automatic offset control technology. It shows that the system can satisfy the requirement of 300 Mb/s laser modulating velocity and 100 mW output power by sinusoidal signal and square signal experiment.