Nanosecond Yb-Doped Monolithic Dual-Cavity Laser Oscillator With Large Core Fiber

A high pulse energy Yb-doped all-fiber dual-cavity laser oscillator is reported, based on the pulse generation mechanism of passive Q-switch with large core fiber saturable absorber. Sequential pulses with 49-ns pulse duration and 21-W average power operating at 1080 nm can be achieved in the scheme using the Yb-doped fiber with the core-diameter of 10 μm. The repetition rate varies from ~1 to 113.6 kHz, while the incident pump power increases. The monolithic all-fiber dual-cavity oscillator can achieve the highest pulse energy of 187 μJ. Moreover, using the all-fiber scheme with the core-diameter of uniform 20 μm, the single-pulse energy can be further scaled up to 484 μJ, which is directly the output from the all-fiber oscillator without additional amplifiers.