Applied Physics B, 127, 43, Feb 2021, DOI: 10.1007/s00340-021-07590-0

Thermal and Optical Performance of Cryogenically-Cooled Laser Diode Bars Mounted on Pin Finned Microcoolers


K. J. Kim1, B. Han2, and A. Bar-Cohen2
1 Mechanical Design Engineering, Pukyong National University, Busan, Korea
2Center for Advanced Life Cycle Engineering (CALCE), University of Maryland, College Park, MD, USA

Abstract:

This study investigates the thermal performance of cryogenic micro-pin fin coolers for high-power laser diode (LD) bars. An open-loop liquid nitrogen cooling system, used to operate LD bars at cryogenic temperatures, is developed and characterized. The comparison study demonstrates that the total thermal resistance value of the micro-pin fin cooler, ranging from 0.03 to 0.04 °C/W, is only 1/3 of that of the micro-gap cooler and, thus, contributes significantly to reducing the LD operating temperature and enhancing its efficiency. In this study, the peak optical power of 68.8 W was observed at an LD bar package base temperature of − 100 °C, providing a 20% increase relative to the optical power of 57.3 W for a nominal operating condition with an LD bar package base temperature of 41 °C. This result clearly illustrates the enhancement in optical performance made possible by cryogenic cooling with a pin fin microcooler.

This article is available online here.

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