High-power QCW arrays for operation over wide temperature extremes

Abstract

A family of laser diode arrays has been developed for QCW operation in adverse environmental conditions. The arrays contain expansion-matched heatsinks, hard solder, and are built using a process that minimizes the packaging-induced strain on the laser diode bars. The arrays are rated for operation at 200 Watts/bar under normal operating conditions. This work contains test results for these arrays when run under a variety of harsh operating conditions. The conditions were chosen to mimic those required by many military and aerospace laser programs. Life test results are presented over a range of operating temperatures common to military specifications (-40 °C to + 70 °C) at a power level of approximately 215 Watts/bar. The arrays experienced no measurable degradation over the course of the life test. Operation at the temperature extremes did not introduce any additional detectable failure mechanisms. Also presented are results of characterization and reliability tests conducted at cryogenic temperatures. Diode arrays have been subjected to repeated cycles in rapid succession between room temperature and 77 K with temperature ramp rates up to 100 K/minute. Pre- and post- thermal cycle P-I-V data are compared. The results demonstrate the suitability of these arrays for operation at cryogenic temperatures.