Temperature-dependent characteristics of GaN-based laser diodes

Gallium nitride (GaN)-based laser diodes (LDs) have emerged as pivotal light sources for high-speed visible light communication, underwater optical links, quantum and atomic systems. There is a growing demand for visible LDs that operate beyond room temperature conditions, which has not been well investigated. In this work, we carry out a comprehensive experimental investigation into the temperature dependence of the electro-optical and frequency response characteristics of blue GaN LDs over a wide temperature range from 283 K to 363 K. The impact of structural design parameters, including the quantum-well number and cavity length, on the thermal stability has been experimentally studied. Experimental results demonstrate that triple quantum wells (TQWs) LDs exhibit better temperature stability in both electro-optical and dynamic characteristics than the double quantum wells (DQWs) LDs and the single quantum well (SQW) LDs. Additionally, LDs with a longer cavity (700 µm) show enhanced heat dissipation over LDs with a short cavity (300 µm), suggesting the importance of thermal management in device design. These findings provide important design guidelines for developing blue LDs suited for harsh-environment and high-temperature applications.