Photonic Generation of Microwave Pulse Using a Phase-Modulator-Based Sagnac Interferometer and Wavelength-to-Time Mapping

We report a new photonic microwave pulse generator using a phase-modulator-based Sagnac interferometer (PM-SI) and wavelength-to-time mapping in a dispersive element. The key significance of the proposed scheme is that the phase of the generated microwave pulse can be continuously tuned by adjusting the bias voltage applied to the PM. Thanks to the wide bandwidth of the PM, high-speed phase modulation of the microwave pulse can be realized. Moreover, the PM-SI is polarization independent, which means that the PM-SI is insensitive to the state of polarization of the input optical signal, ensuring a stable operation of the system. The proposed scheme is theoretically analyzed and experimentally verified.