基于光子芯片的微波光子混频器(特邀)

Chip-based microwave photonic frequency mixer(Invited)

提出了一种由光生本振单元和波长分离调制单元组成的微波光子混频方法,并在绝缘体上硅材料上设计实现了上述波长分离调制芯片。该芯片集成了硅基相位调制器、微环滤波器、光电探测器、光耦合器和光栅耦合器。实验搭建了基于该波长分离调制芯片的微波光子次谐波混频系统,结果表明,该微波光子混频器可以将6~16 GHz的RF信号变频到33~23 GHz。此外,针对实验系统中残留的混频杂散,分别提出了增加微环滤波器抑制比降低泄露光生本振强度和引入光移相器修正泄漏光生本振相位两种解决方案。通过仿真验证可知,引入光移相器的方法更为简单,更适合于光子集成芯片。

A microwave photonic frequency mixer constituted of an optically-carried local oscillator(LO)and a wavelength-division modulator was proposed.The wavelength-division modulator chip,which was consisted of a silicon phase modulator,two micro-ring filters,a photodetector,two optical couplers,and two grating couplers,was designed and fabricated.Based on the chip,a microwave photonic harmonic frequency mixer was implemented.In the experiment,an optically-carried LO was generated by double-sideband suppressed-carrier modulation at a Mach-Zehnder modulator.An RF signal from 6 to 16 GHz was successfully converted into a signal with a frequency of 33 to 23 GHz.In order to suppress the remaining mixing spurs,two solutions,i.e.,increasing the rejection ratio of the micro-ring filter to decrease the intensity of the leaked optically-carried LO and introducing an optical phase shifter to correct the phase of the leaked optically-carried LO,were proposed and verified by simulation.It should be noted that the latter is simpler and more suitable for photonic integration.