V-grooved substrate buried heterostructure InGaAsP/InP laser by one-step epitaxy

Abstract

A V‐grooved substrate buried heterostructure (VSB) InGaAsP/InP laser by one‐step epitaxy emitting at 1.3 μm wavelength is developed. The one‐step epitaxy VSB laser is realized by using Cd diffusion for the formation of the p‐InP internal current restriction layer. Efficient current restriction is confirmed in the Cd‐diffused current restriction structure to be comparable to that by two‐step epitaxy. The VSB laser by one‐step epitaxy showed a cw threshold current of about 15 mA at 25 °C and a far field pattern as smooth as that of the two‐step epitaxy VSB laser. The T₀ value was 50–60 K below 55 °C and was 30 K above 55 °C. The threshold current obtained here is the lowest among various InGaAsP/InP lasers by one‐step epitaxy.