Small-signal modulation and differential gain of red-emitting (λ = 630 nm) InGaN/GaN quantum dot lasers

Abstract

We report small-signal modulation bandwidth and differential gain measurements of a ridge waveguide In0.4Ga0.6N/GaN quantum dot laser grown by molecular beam epitaxy. The laser peak emission is at λ = 630 nm. The −3 dB bandwidth of an 800 μm long device was measured to be 2.4 GHz at 250 mA under pulsed biasing, demonstrating the possibility of high-speed operation of these devices. The differential gain was measured to be 5.3 × 10−17 cm2, and a gain compression factor of 2.87 × 10−17 cm3 is also derived from the small-signal modulation response.