A study of the dynamic governing timing restoration in the actively modelocked soliton laser

Abstract

Summary form only given. Low-noise lasers with minimum pulse-to-pulse timing jitter are of interest for numerous applications, including high-speed optical communications and precision optical sampling. Timing jitter smears out the certainty in the arrival time of the pulse and can lead to degradation of bit-error-rate in the former case, and of fidelity and dynamic range of the sampled data in the latter. Haus and Mecozzi (1993) derived a general theory of the noise in a mode-locked laser, resulting in coupled equations of motion governing the evolution of the pulse parameters-pulse energy, phase, carrier frequency, and timing-driven by noise. From those equations, one can derive characteristic damping rates that govern the laser's timing response to noise. Building a laser with minimal timing jitter, in principle, and in practice, requires an understanding its dependence on parameters such as group-velocity dispersion (GVD), effects of amplitude and phase modulation depth, strength of filtering. The major contributions of the work are as follows: we show experimental measurements of the damping constants governing pulse retiming using a microwave phase noise measurement. We have extended the theory of Haus and Mecozzi to include the case of modelocking with phase modulation, and we compare the damping rates with those given by amplitude modulation and discuss the implications for the design of an actively modelocked laser with minimum timing jitter.