Impact of gain compression factor on modulation characteristics of InGaAs/GaAs self-assembled quantum dot lasers

Abstract

This paper investigates the influence of gain compression factor on the modulation response of InGaAs/GaAs self-assembled quantum dot laser based on rate equations. For different gain compression factors the output power-current characteristics, light emissions of quantum dot laser have been simulated and effect of gain compression factor changes on quantum dot laser is illustrated. Also, small and large-signal response of quantum dot lasers is studied and the impact of the gain compression factor is presented. It explains that increase of gain compression factor, decreases small-signal modulation characteristics, nevertheless, improves large-signal response of quantum dot lasers. It helps to generate better laser signal quality, higher eye and smaller jitter. The large-signal behavior of a laser diode determines its capability for digital data transfer. The modulation speed of quantum dot lasers is of specific importance if such lasers are considered for optical communication systems.

Impact of linewidth enhancement factor and gain suppression on chirp characteristics of high-speed laser diode and performance of 40 Gbps optical fiber links

“…Moreover, the increase of ε enhances the effect of α-factor in the blue wavelength shifting that agrees with the results in Ref. [37] through the reduction of differential gain above threshold [32,50]. These obtained results, to the best of the authors' knowledge, represent new contributions to dependency of the lasing wavelength shifts on α and ε for 40-Gbps WDM systems.…”

Optimum thickness of GaAs top layer in AlGaAs‐based 850 nm VCSELs for 56 Gb/s PAM‐4 applications

“…Therefore, for more realistic simulation results, we have considered the proportionality of ε to τ p , which results in the thickness of the GaAs top layer influencing the modulation characteristics. We assumed that ε = 1.927 × 10 −11 τ p [ 7,9 ].…”

“…Traditionally, the gain-saturation coefficient is considered as being independent of the photon lifetime. However, the increased photon lifetime owing to the change in the top-layer thickness of GaAs changes the gain-saturation coefficient, and this coefficient is both experimentally [ 7 ] and theoretically [ 9,10 ] found to be linearly proportional to the photon lifetime. Therefore, in optimizing the VCSEL performance for PAM-4 applications, wherein the requirements are stringent, this effect should be carefully considered.…”