All-Polarization-Maintained Microwave Photonic Phase Detector Based on a DP-DMZM

An all-polarization-maintained microwave photonic phase detector (MPPD) based on a dual-polarization dual-drive Mach-Zehnder modulator (DP-DMZM) is demonstrated to detect the phase difference between a microwave signal and an optical pulse train. The robustness of the MPPD can be significantly improved with the all-polarization-maintained structure. A proof-of-concept experiment is carried out. An 8.032-GHz dielectric resonator oscillator (DRO) is locked to an optical pulse train through this MPPD with its phase noise reducing from −109.68 dBc/Hz to −135.41 dBc/Hz at 10-kHz offset frequency. The DP-DMZM-based MPPD shows that the minimum value of the noise floor is around −154 dBc/Hz, and the integrated residual timing jitters from 100 Hz to 100 kHz, 1 MHz, and 3 MHz are 276 as, 696 as, and 2.50 fs, respectively. The MPPD has good stability against external vibrations and stresses.