Microwave Photonic Multifunctional Phase Coded Signal Generator

Abstract

A novel phase coded signal generator is proposed and experimentally verified. The scheme consists of a dual-polarization quadrature phase shift-keying (DP-QPSK) modulator and a phase modulator in a Sagnac loop. By properly adjusting the bias voltages of the DP-QPSK modulator and the polarization direction of the signal, two-order optical sideband is polarization separated from the carrier and −2-order sideband. We can modulate the two-order optical sideband with phase coded data and two phase coded signals will be generated which are the beating products between the modulated two-order optical sideband and the unmodulated optical sidebands in balanced detector. The distinct advantage of our approach is that we integrate multiple functions into a compact system which can simultaneously generate dual-band and multi-phase coded signal with doubled and quadrupled frequency. In the experiment, 1-Gbit/s binary and quaternary phase coded signals with 11 and 22 GHz carrier frequencies are generated by using of a 5.5 GHz local oscillator signal.