High-frequency characteristics of directly modulated InGaAsP ridge waveguide and buried heterostructure lasers

TLDR

The study investigates the high‑frequency modulation characteristics of InGaAsP ridge waveguide lasers at 1.55 µm and etched‑mesa buried heterostructure lasers at 1.3 µm. The authors develop small‑ and large‑signal circuit models for both devices, identify the key factors shaping their high‑frequency response, and model the observed damping with field‑dependent optical‑gain compression in the rate equations. The results show that electrical parasitics dominate the small‑signal response of the EMBH laser, limiting its large‑signal turn‑on and turn‑off times, and that both devices exhibit strong damping of relaxation oscillations.

Abstract

The high-frequency modulation characteristics of InGaAsP ridge waveguide lasers at 1.55 μm and etched mesa buried heterostructure (EMBH) lasers at 1.3 μm are investigated. Small-signal and large-signal circuit models are developed for both devices, and the main factors which influence the high-frequency modulation response are established. It is shown that the electrical parasitics in the chip dominate the small-signal frequency response of the EMBH laser and limit the large-signal turn-on and turn-off times. The small-signal and large-signal responses of both devices show strong damping of the relaxation oscillations. This damping can be modeled accurately using field-dependent optical gain compression in the rate equations.