Passive, Low Cost, Diffraction-Limited Fiber Optic Laser Beam Delivery

The U.S. Navy has a requirement for a fiber optic system which can deliver high power, diffraction-limited laser beams without significantly altering their beam quality. In response to Navy needs, U.S. Laser Corporation proposes a Phase I SBIR program to demonstrate efficient, M_-preserving fiber optic beam delivery of 1064 nm and 532 nm Q-switched diffraction-limited lasers. Under a previous Phase II SBIR for the Air Force, U.S. Laser demonstrated beam quality preserving fiber delivery for multimode industrial lasers. In this Phase I program, U.S. Laser will extend this technology to the diffraction-limited case. US Laser's M_-preserving fiber technology is based on proper understanding of the physics and mode coupling properties of Gradient index fibers. In contrast to complicated phase conjugation techniques which rely on nonlinear effects, USL's technique is passive, linear, and independent of wavelength and power level. This makes it useful in many situations where phase conjugation is not feasible. This technology is currently untested for TEM00 lasers. In this Phase I study, US Laser will extended this technology to the diffraction limited (M_=1-1.5) regime, to allow M_-preserving delivery through large core optical fibers. In addition, U.S. Laser will demonstrate highly efficient delivery, yielding >95% total system throughput of all laser power.