All-optical clock extraction for CSRZ modulation data

Abstract

This paper demonstrates a theoretical investigation on clock extraction from carrier-suppressed return-to-zero (CSRZ) modulation format data at 40?Gbit/s by using a semiconductor optical amplifier (SOA)-based ring laser. A completely numerical analysis about the clock characteristics at 40?Gbit/s is done, which is an effective guide for the experiment and necessary to optimize system performance. The crucial parameters, including the pulse width, energy of the CSRZ data signals and influence of SOA bias current, are analyzed because they determine the quality of the recovered clock pulses. Meanwhile, simulation results show that high-quality clock extraction from 2⁷―1 pseudo-random binary sequence (PRBS) CSRZ data at 40?Gbit/s can be achieved by using higher power assisting continuous-wave (CW) light into a SOA-based ring laser.