High-Resolution Microwave Frequency Measurement Based on Optical Frequency Comb and Image Rejection Photonics Channelized Receiver

Abstract

A high-resolution microwave signal frequency measurement scheme based on optical frequency comb (OFC) and an image rejection microwave photonics channelized receiver is proposed. The scheme consists of two branches. The OFC is generated by cascaded Mach-Zehnder modulators (MZMs) in the upper branch. The optical carrier is frequency shifted by the optical frequency shifter (OFS) in the lower branch. The shifted optical carrier is sent to polarization modulator (PolM) to be modulated by the RF signal to be measured. The signal from the upper and lower branches are injected into 90-degree optical hybrid and divided into four outputs. The optical signal of each output is divided into channels by the wavelength division multiplexer (WDM) and beat by the balance photodetector (BPD). The back-end of the scheme adopts image rejection down-conversion method to prevent spectral aliasing in the measurement process. Simulation verifies the effectiveness of this scheme. The results show that the scheme can accurately measure microwave signals within the frequency range of 1-79 GHz.