Laser Beam Delivery Sub-System for Multi-Band Mid-Infrared Laser

High power midwave infrared (2f{5 fYm) lasers are currently used in infrared countermeasure (IRCM) systems. The objective of this SBIR is to develop high efficiency laser beam delivery system. Current beam delivery methods for IRCM systems are manufactured from free-space optics or midwave multimode fibers. Free-space beam delivery has limited reliability, is heavy and requires complex packaging for mitigating environmental and vibration effects. Beam delivery via multimode fibers meets the requirement of compactness and lightweight but offers poor mode quality. Single-mode fibers are the only choice for transporting high beam quality multi-band mid-infrared lasers in IRCM systems. The single-mode fiber systems will be compact, lightweight, have excellent mode quality, multi-kilowatt power transmission capacity, minimal loss, and large bandwidths. Such single-mode fiber can be developed from existing fiber fabrication technologies. The proposed work will demonstrate feasibility of producing innovative chalcogenide glass single-mode fibers specially designed to enable high quality low-loss transmission of high power midwave infrared (2f{5 fYm) laser beam. These unique fibers provide the platform for designing a beam delivery system with large bandwidth, robust, compact, lightweight, high brightness, and good beam quality for next-generation IRCM systems.