Analysis of thermal characteristics of microchannel-cooled photonic crystal laser diode bars

Photonic crystal laser diode bars have the advantages of low vertical divergence angle and high resistance to catastrophic optical mirror damage. However, with the increase of output power, the waste heat problem is becoming more serious, affecting the further improvement of laser performance. Therefore, it is of great significance to study the thermal characteristics of bars. In this paper, the fluid-solid coupling conjugate heat transfer model of a microchannel cooled photonic crystal laser diode bar is established through the Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) numerical methods. The transient thermal behavior, steady-state characteristics, and temperature distribution of photonic crystal laser diode bars under continuous (CW) operating states are studied in detail. The simulation results show that the junction temperature is 55.48°C, and the thermal resistance is 0.48 K/W. The closer the emitter is to the bar center, the easier the thermal crosstalk occurs. In the experiment, the continuous output power of the photonic crystal laser bar is 112.13 W at 120 A, the junction temperature is 57.14 °C, and the thermal resistance is 0.50 K/W. The simulations of bars are consistent with the experiment.