Broadband Microwave Photonic Splitter With Arbitrary Amplitude Ratio and Phase Shift

Abstract

We report a broadband 1 x N microwave photonic splitter (MPS) with arbitrary amplitude ratio and phase shift. The key devices used in the MPS are a polarization modulator (PolM), an optical bandpass filter (OBPF), polarization controllers (PCs), and polarizers (Pols). The cascaded PolM and OBPF generate an orthogonally polarized single-sideband modulated optical signal. The phase difference between the two orthogonal components and the state of polarization of the optical signal can be adjusted by the PC independently. After the polarization-to-intensity modulation conversion by the Pol, the microwave is recovered in the PD. The amplitude and phase of the microwave signal can be independently tuned by adjusting the three plates of the PC. The proposed MPS is theoretically analyzed and experimentally verified. Broadband MPS with bandwidth from 8 to 40 GHz is successfully achieved. In addition, we apply the proposed MPS to a two-tap microwave photonic filter (MPF). The notch position and depth of the MPF are tunable by adjusting the phase shift and amplitude ratio between the two optical branches, respectively.