All-fiber high power tunable thulium laser amplifier around 1850 nm

Our work demonstrated a tunable Polarization Maintaining (PM) thulium-doped fiber two stages amplifier system spanning the 1820–1880nm range with a fiber-coupled output power as high as 30W CW. In addition, the high-power booster stage is made using double clad fibers pumped with 793nm laser diodes wich contrasts with the usual core-pumping using Erbium-Ytterbium laser sources emitting around 1570nm. To the best of our knowledge, this marks the first reported demonstration of a 30W level all-fiber PM TDFA Master Oscillator Power Amplifier (MOPA) operating within the 1820–1880nm wavelength regime. The significance of this achievement extends to a wide array of applications, including but not limited to quantum computing.