A method for suppressing frequency drift of integrated microwave photonic filters based on difference scheme

Abstract

Frequency drift of a conventional microwave photonic filter is due to relative frequency fluctuation between optical carrier and photonic filter, which hinders its practical application. In this paper, a method based on difference scheme for suppressing frequency drift of integrated microwave photonic filters is proposed. By utilizing an on-chip high-Q Si3N4 microring resonator as a frequency monitoring unit to track the frequency drift of optical carrier, the center frequency of the photonic filter is simultaneously tuned to follow the variation of carrier. In this way, the frequency drift caused by optical carrier and photonic filter can be eliminated together based on difference effect. Compared with the conventional microwave photonic filter without difference scheme, the frequency drift in one hour measured in experiment is reduced from 700MHz to 75MHz.