基于科斯塔斯锁相环的光学零差相干接收技术

Optical homodyne coherent receiver based on digital Costas optical phase locked loop

零差相干光通信能够实现极高的通信速率和接近量子极限的灵敏度,是新一代空间通信领域极具潜力的通信体制。以窄线宽激光器作为本振源,结合90°光学混频技术和科斯塔斯光学锁相环技术,实现了信号光的零差相干接收。试验结果表明,信号光和本振光经过90°光学混频后I、Q两路信号相位差保持90°,科斯塔斯光学锁相环可以长时间实现信号光和本振光之间的相位锁定,接收速率为2Gbps的二进制相移键控(BPSK)信号,试验结果表明,该接收机能够很好地实现基带信号解调。

Homodyne coherent optical communication can achieve very fast communication rate and the quantum limited sensitivity. It is one of the most potential technology in the field of space communication. Taking the narrow line width DFB laser as local oscillator,combined with 90° optical mixing and Costas digital optical phase locked loop technique,optical homodyne coherent reception was realized. The experimental results indicate that after the two lasers transmit through the 90° optical mixing,the phase difference between I branch and Q branch will keep 90° for a long time. Costas digital phase locked loop can lock the phase difference between the two lasers for a long time. By receiving the 2Gbps BPSK optical signal and correcting the output signal with the technique of the baseline recovery technology and magnitude judgment,the baseband signal can be well demodulated.