Thermal effect on optical characteristics of packaged edge emitting laser diode with compressively strained multi-quantum well structure

Thermal effect on the device characteristics plays a critical role for its applications. In case of semiconductor distributed feedback (DFB) diode laser, because the gain bandwidth and the Bragg wavelength do not necessarily have the same responses to the environment temperature, those properties for maintaining a stable single longitudinal mode (SLM) have to be considered. If the two wavelength shifts are not optimized, even though a single mode is achieved at certain temperatures by index Bragg grating, the DFB laser can suddenly appear lasing in multimodes by the Fabry-Perot (FP) cavity in any other thermal conditions. This work investigates experimentally the optimum condition for the fabricated edge emitting laser diode at 1.55¿m incorporating pseudomorphic compressively strain multi-quantum well (MQW) with a transistor-outlined (TO) package operating from -40°C to 85°C for achieving stable single longitudinal mode. Optical characteristics are measured such as wavelength detuning, threshold current, and slope efficiency as figures of merit depending on the temperatures.