High power, compact, passively Q-switched Ho-doped fiber laser tandem pumped by a 1150 nm Raman fiber laser

We present a compact passively Q-switched Ho-doped fiber laser (HDFL) with a maximum average output power of 16.1 W. The HDFL was pumped by a high power 1150 nm Raman fiber laser. A piece of 4 m long Ho-doped fiber in the HDFL’s cavity was used not only as the gain medium but also as the saturable absorber. A stable Q-switched pulse train was obtained in this HDFL and the repetition rate covers from 80 to 218 kHz with a pulse duration of 1.6 ~ 0.72 μ s. The central wavelength locates at 2049.9 nm at the beginning and broadens and blue-shifts as the pump power increases. This is the first demonstration of passively Q-switched HDFL pumped by a 1150 nm Raman fiber laser with the highest average output power. Passively Q-switched pulse trains in HDFLs, employing an additional piece of Ho-doped fiber as the saturable absorber, were also investigated.