Efficient chirped-pulse amplification based on thulium-doped ZBLAN fibers

Abstract

We demonstrate a chirped-pulse amplifier system operating around 1900 nm using thulium-doped ZrF4–BaF2–LaF3–AlF3–NaF (ZBLAN) fibers. The pulses from a thulium-doped ZBLAN fiber laser oscillator are stretched by a passive ZBLAN fiber and subsequently amplified in a double-clad thulium-doped ZBLAN fiber to an average power of 6.9 W at a pump power of 17 W. We found that ZBLAN fibers require a much lower pump and/or seed power than silica fibers for efficient amplification. The amplified pulses are compressed to a duration of 150 fs with an average power of 3.9 W.