Abstract

High-speed operation of InGaAsP lasers is one of the most interesting current topics in optical fiber communications.^1,2 It has been pointed out that the damping due to nonlinear gain greatly affects the dynamic characteristics, such as modulation bandwidth,² the damping of ringing of relaxation oscillation,³ and the transient frequency chirp.⁴ Conventional methods to estimate the nonlinear damping factor γ_n (Refs. 2 and 5) require careful calibrations for parasitic effects and detector response. We propose here a parasitic-free way to measure γ_n by measuring the phase difference in detected FM and AM signals.

© 1989 Optical Society of America