Broadband and linearized photonic time-stretch analog-to-digital converter based on a compact dual-polarization modulator

Abstract

A broadband linearization scheme for a photonic time-stretch (PTS) analog-to-digital converter (ADC) is proposed based on a dual-polarization binary phase-shift keying (DP-BPSK) modulator with complementary parallel single-sideband (SSB) modulation. In this system, two stretched radio frequency signals, corresponding to the two orthogonal polarizations of the DP-BPSK modulator, are complementary, which can realize differential operation to eliminate the second-order harmonic distortion and pulse envelope distortion. Meanwhile, SSB modulation is used to avoid dispersion-induced power fading. Theoretical analysis and simulation results show that the proposed scheme can effectively improve the linear performance of PTS ADC, even considering the polarization-dependent delay deviation and amplitude offset.