Diode arrays for high-temperature operation in military environments (Conference Presentation)

Many military applications require reliable laser diode operation across a wide range of elevated temperatures. Size, Weight and Power (SWaP) restrictions often limit cooling options and necessitate that high-power emission at the desired pump wavelength is maintained across wide temperature ranges. A family of QCW diode arrays has been developed for operation in these harsh environments. The arrays may be constructed with either multi-wavelength diode bars or wavelength locked with Volume Bragg Gratings (VBGs) to optimize absorption across a wide range of temperatures. The arrays have been designed to withstand the mechanical shock and vibration requirements common to military environments. This paper includes a comparison of the multi-wavelength arrays and VBG-locked arrays at high temperatures. Both sets of arrays were characterized across a broad temperature range and exposed to MIL-STD shock and vibration testing. VBG locked arrays are shown to provide >90% locking across a 15° operating range whereas multi-wavelength arrays allowed power absorption to be maintained across incredibly wide ranges (e.g. -40° to 70°C). Life test results from arrays operated at 80oC, 250A, 60Hz for over 600 million pulses are also presented. These arrays demonstrate excellent high-temperature reliability over a pulse count well in excess of the requirement of many military applications (e.g. range finders / target designators).