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

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.