Study of thermal characteristics of high-power photonic crystal laser diodes with CS-mount package

Photonic crystal laser diodes are characterized by low divergence angle and high brightness, but thermal effects have become a major obstacle to further improvement of output power and efficiency. The thermal characteristics of high- power photonic crystal laser diodes are of great importance to improve the output power and increase the lifetime. In this paper, the physical heat dissipation model of a single photonic crystal laser diode with CS-mount package is established. Steady-state thermal characteristics simulations are performed using the Finite Element Method (FEM) and the influences of different parameters, such as solder, transition heat sink and heat sink on the thermal characteristics are analyzed. The simulation results show that the thickness and thermal conductivity of the heat sink materials are the main factors impacting the heat dissipation of the laser. The thermal resistance of the laser can be reduced effectively by using heat sink materials of high thermal conductivity. On the premise of ensuring wettability and reliability, the thickness of the solder layer should be decreased. A photonic crystal laser diode with a cavity length of 4 mm and a stripe width of 350µm based on an optimized heat dissipation structure is designed and fabricated. The CW output power of 41.9W, the vertical divergence angle of 18.48° and the thermal resistance of 1.54 K/W are obtained under the injection current of 50A at 20 ℃.