Investigation of heat-spreaders as a passive thermal management element in SWIR fiber lasers

This article examines the utility of heat spreaders as an alternative to conventional heat management techniques for fiber lasers and amplifiers by numerical modeling scalable for prediction of heat loads in high power laser amplifiers and the model’s experimental verification. A special focus is placed on the section of a fiber splice, given its importance and potential issues associated with signal loss and subsequent heat generation during laser operation. Temperature change is analyzed and compared both numerically and experimentally for three passive cooling architectures: a loose, recoated fiber splice attached to a copper plate via Kapton tape, a recoated fiber splice placed in a thermal interface material (TIM) filled U-shaped groove in an aluminum plate, and finally a non-recoated splice placed in a heat-spreader, with the recoating material serving instead of TIM. The benefits and utility of fiber heat spreaders are shown and discussed, and their superior thermal transfer rate is demonstrated.