The research on temperature distribution of GaN-based blue laser diode

• The 3-D temperature distribution of LDs are obtained by infrared camera.
• Transient thermal technique is applied to get the component thermal resistance.
• The main heating sources are studied.

Blue GaN-based laser diodes (LDs) have been characterized by thermal infrared imaging and transient thermal technique to obtain temperature distributions along the optical resonant cavity under continuous-wave (CW) operation. The highest temperature occurred at the emitting facet and the second higher temperature occurred in the other reflecting facet under injection current I = 100 mA with platform temperature of 308.15 K. The results are attributed to the nonradiative recombination in the active region and the reabsorption of laser light inside the cavity. And due to the different of optical flow density, the highest temperature appears in emitting facet. Based on diode forward voltage with temperature, transient thermal technique is used to obtain the temperature distribution along the top-down direction of LDs by the structure function method. The thermal resistance from chip to case is 47.3 K/W. The chip’s thermal resistance is the main contribution.