Narrow-Band and Low SWaP Diodes in Tough Environments

摘要

High Power multi-kW class fiber lasers have become a leading technology in Directed Energy applications. With Direct Energy weapons and countermeasures moving closer to a deployable technology, industry players are now looking to ensure the components within their systems can withstand the harsh environments in which they will be used. With limited power available in the field, efficiency is a key criterion for these systems and there is a careful balance for diode laser pumps as a piece of the overall system. Increasing the cooling capacity delivered to the diode pumps will increase their Electrical-to-Optical efficiency, but requires more energy be consumed in the cooling loop through lowering the coolant temperature or increasing the pump speed to increase flow rate. In this paper, Coherent|DILAS aims to map these uncharted waters for its Low SWaP diode lasers by exploring trade space for the parameters that are critical to the overall system efficiency. By changing coolant types from water to glycol mixes, coolant freezing can be eliminated while the effects of coolant viscosity are explored. Additionally, direct changes to the coolant temperature and flow rates further explore cooling/efficiency trade space. Experiments are then repeated with an external grating to lock the center wavelength at the 976nm absorption band. The range at which locking is maintained and the efficiency change will be explored for various coolant, flow, and temperature configurations. With a large web of interacting processes being explored, Coherent|DILAS aims to enable further overall system optimization within Directed Energy community.