A scheme for generating multi-channel chaotic signals with time-delay signature suppression

Abstract

Based on a weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) with dispersive optical feedback provided by a linearly chirped fiber Bragg grating (LCFBG), we propose a scheme for simultaneously generating multi-channel chaotic signal with time delay signature (TDS) suppression. The experimental results show that under LCFBG feedback, 45 longitudinal modes within a 30-dB amplitude variation in the WRC-FPLD can be simultaneously driven into chaotic states. With the increase of feedback strength, the effective bandwidth of the generated chaotic signal gradually increases while the TDS value firstly decreases and then increases. For feedback strength from -35 dB to -15 dB, the generated chaotic signals by WRC-FPLD under LCFBG feedback possess lower TDS compared with those under mirror feedback or ring cavity feedback. Under an optimized feedback strength of -32.88 dB, the TDS value is about 0.01, which means the TDS is almost completely suppressed.