基于光频率梳的宽带微波光子镜像抑制下变频

Large-bandwidth Microwave Photonic Image-Reject Mixer Based on Optical Frequency Comb

文章提出了一种基于微波光子技术的宽带镜像抑制下变频方案。在本方案中,利用两个强度调制器(intensity modulators,IM)构成梳线间隔为3-GHz的光频率梳,可以将2GHz^40GHz的微波信号下变频为0~1.5GHz的中频(IF,Intermediate Frequency)信号。基于90°光耦合器构成的Hartley结构,本方案实现镜像抑制下变频。仿真验证了此方案的有效性,在2GHz^40GHz的频率调谐范围内,镜像抑制比可以达到67 dB,动态范围为100 dB·Hz 2/3。

A photonic microwave image rejection mixer with large operation wideband is proposed.In this scheme,two intensity modulators(IM)are used to form an optical frequency comb with a frequency interval of 3 GHz,and the received RF signal of 2 to 40 GHz can be down-converted to an intermediate frequency(IF)signal of 0 to 1.5 GHz.The image-reject down-convert I/Q mixer is realized by Hartley structure composed of a 90°hybrid coupler.In order to verify the effectiveness of this scheme,an simulation experiments is performed.The simulation results show that within the frequency tuning range of 2GHz^40GHz,the image rejection ratio can reach 67dB and the dynamic range is 100dB·Hz 2/3.