All-fiber laser with simultaneous Tm³⁺ passive Q-switched and Ho³⁺ gain-switched operation

Abstract

We experimentally demonstrate simultaneous Tm passive Q-switched (PQS) and Ho gain-switched laser operations at 1888.8 and 2021.2 nm, respectively, in a single-cavity all-fiber laser. The PQS operation of the Tm laser is based on the use of a high-concentration holmium-doped fiber as a fiber saturable absorber. Then the Tm laser emission is used as a pulsed pump source to achieve Ho gain-switched pulses. A high birefringence fiber optical loop mirror used as a spectral filter allows the tuning of both Tm and Ho laser emissions.