Instantaneous microwave frequency measurement system based on a simplest integrated microwave photonic filter

摘要

A simplest integrated microwave photonic filter (IMPF) is proposed and designed as an optical discriminator for instantaneous microwave frequency measurement (IMFM). Amplitude comparison functions (ACFs) of the IMFM system based on a Mach-Zehnder modulator (MZM) and a phase modulator (PM) are theoretically deduced and analyzed. Simulation results demonstrate that by designing the IMPF with lengths of L-1=0.5 mm and L-2=1 mm, and simultaneously tuning optical carrier of the MZM at one valley, one peak of the spectral response, the IMFM system with measureable range from DC to 35 GHz and ACF slope of 29 dB can be obtained. In addition, when using a PM, the monotonic frequency range is 0 Hz to 35.3 GHz with the ACF slope is 84.1 dB. However, from 4 GH to 32.1 GHz the ACF slope is only 17.6 dB. Both theoretical and simulation results indicate that based on such simplest IMPF a new approach with advantages of compact structure and better reconfigurability can be established for the IMFM.