This SBIR proposal presents two innovative high energy fiber laser component technologies that will significantly advance high power all-fiber eye-safe fiber lasers without causing damage to the fiber. The first one is a coherent all-fiber beam combiner and the second one is an efficient fiber side-pumping technique without using free space optics. Utilizing these two components, a large number of high power Tm-doped fiber lasers can be coherently combined to emit the fundamental in-phase mode at the eye-safe wavelength (ë = 1.9 ìm). The output power scales not only with the core density but also with the fiber length far exceeding the absorption length without introducing nonlinear effects. This proposal describes these two technologies in great detail and presents a working plan to develop these components in such a way that they will work well together and provide highest slope efficiency and output power in a high-brightness beam. Under Phase I, a design analysis will be completed for a side-pumped all-fiber, phase-locked, Tm-doped fiber laser that can deliver an output power greater than 1kW (CW) at an eye-safe wavelength. It is envisioned that technologies developed under this SBIR program will provide the US Army Space and Missile Defense Technical Centers with much improved components for their advance fiber laser program.
Keywords: Fiber Lasers, Eye-Safe, High-Power, Fiber Combiners, Phase-Locking, Side-Pumping, Multicore, Photonic Crystal.
