为了实现多通道的微波光子下变频, 提高变频链路性能, 提出一种使用单个集成调制器实现的微波光子下变频方案, 该方案利用偏振复用特性实现双通道下变频功能。仿真与实验结果表明: 当子调制器设置在最小传输点时, 可实现载波抑制双边带调制, 光载波抑制比达到29 dB；双通道分别独立地将射频信号下变频转换为中频信号, 杂散抑制比达30 dB左右, 2个通道的无杂散动态范围(SFDR)分别达到110.4 dB·Hz2/3、113.4 dB·Hz2/3。

In order to realize multi-channel microwave photonic down-conversion and improve the performance of frequency conversion link. In this paper, a single integrated modulator is used to realize the microwave photonic down-conversion scheme, the scheme uses the polarization multiplexing feature to realize the dual-channel down-conversion function. The simulation and experiment results show that when the sub-modulator is set to work at the minimum transmission point, the carrier-suppressed double-sideband modulation is realized, and the optical carrier-suppression ratio reaches 29 dB. Two channels independently down convert the radio frequency signal to intermediate frequency signals respectively, the spurious rejection ratio reaches about 30 dB, and the spurious free dynamic range(SFDR) of two channels reaches 110.4 dB·Hz2/3 and 113.4 dB·Hz2/3 respectively.