External cavity multiwavelength semiconductor mode-locked lasers gain dynamics

The gain dynamics of a semiconductor optical amplifier ( SOA) were measured using pump-probe techniques for the amplification of 750 fs pulses, 6.5 ps pulses and multiwavelength pulses, obtained from an external cavity semiconductor mode-locked laser. Furthermore, the intracavity gain dynamics of an external cavity semiconductor mode-locked laser was measured under multiwavelength operation. The experimental results show how the inherent chirp in pulses from external cavity semiconductor mode-locked lasers result in a slow gain depletion without significant fast gain dynamics. This mitigates gain competition between wavelength channels and nonlinearities in the gain media ( SOA), enabling the multiwavelength operation of external cavity semiconductor mode-locked lasers. Numerical simulations support the experimental results