Realization of fiber lasers with output power in the multi-kW range critically depends on the development of high power fiber components. This proposal specifically addresses the design, development and manufacture of new, all-fiber pump couplers using large-core, single-mode Chirally-Coupled Core (CCC) fiber, capable of operating at pump powers as high as 2kW or more. To improve the performance of pump combiners, we are proposing a new approach developed by AGT Laser (formerly FG2 Tech) using a specially designed coupling piece between the pump fibers and the signal DCF. This approach is a side-coupler design that allows for the DCF to remain continuous inside the coupler. This novel design eliminates the problem of matching cores when splicing the coupler signal fiber to an additional DCF, as is required in the end-pumping approach. This approach is fundamentally independent of the particular type of DCF and can therefore allow the use of a novel and demonstrated highly-scalable mode area, single-mode optical fiber that can incorporate polarization maintaining performance.
Benefit: We propose a novel pump coupling scheme that will benefit virtually any fiber design that incorporates a pump-guiding clad, whether it is polymer, air-clad, or glass clad, and with any type of doped or updoped fiber with 250 or 400 micron diameter. This design, when it incorporates Polarization Maintaining Chirally-coupled core optical fiber, will be a key to realizing fiber lasers in High Energy Laser weapons programs or commercial applications such as EUV lithography, where higher output powers with high mode quality, narrow linewidth and polarization control are preferred.
Keywords: optical pump coupler, optical pump coupler, high power fiber laser component, optical fiber device, optical pump and signal combiner
