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Thermal Characteristics of Back Cooled Impingement Cooler for Packaging of High Power Semiconductor Laser Diode Arrays

A simple impingement type of water cooled heat sink has been fabricated and characterized for packaging of high power semiconductor laser diode arrays. A single chilled water jet impinging normally on the back plane of copper submount is used to achieve enhanced heat transfer coefficient for convective cooling. The cooler is fabricated out of copper (OFHC), which consists of a chamber (3x9x12 mm3) with one pair of inlet and outlet tubes for chilled water flow at one end and 3 mm thick copper submount at the other end. The thermal characteristics of the cooler is measured as a function of heater power, heater temperature and chilled water pressure of up to 30PSI. The minimum thermal resistance obtained is 0.6°C/Watt for submount surface area of 3.2 x 10mm2. Experimental thermal resistance values closely match with theoretical calculations. The heat sink fabrication and characterization are discussed.