All-Fiber Widely Tunable Thulium Laser
We present results from an all-fiber thulium laser system that can be tuned to any wavelength between 1710 – 2110 nm, without using any moving mechanical parts. An acousto-Optic tunable filter (AOTF) is used as the tuning element, which allows for the wavelength to be tuned in ~ 20 μs. Core-pumped and cladding pumped thulium fibers are used to enable lasing action across the wavelength range.
We use in-house fabricated fused fiber couplers and combiners that have a flattened coupling response with wavelength to allow for the system to be built in an all fiber design. These couplers have a coupling response that only varies by +/-10% over the 400 nm operating range.