Gain characteristics of 1.3 μm compressively strained MQW lasers at high temperature

With an aim toward low drive current operation of 1.3 μm InGaAsP/InP MQW lasers at high temperature, fundamental device parameters of compressively strained MQW structures were measured at 85°C. Increased gain coefficient and reduced transparency current density are obtained for the compressively strained quantum well. As the compressive strain increases, the internal quantum efficiency is increased, while the internal loss tends to increase. Using the parameters obtained, the device structures were optimized to realize low drive current at high temperature. A low threshold current of less than 5 mA and the record operation current as low as 20 mA under 5 mW output power were obtained for the LD at 85°C.