Quasi-continuous-wave-pumped thulium-doped fiber laser with 0.2 kW of instantaneous output power

TL;DR

This paper reports a quasi-continuous-wave thulium-doped fiber laser achieving 198 W instantaneous power in short pulses, with high efficiency and simplified thermal management, demonstrating potential for high-power pulsed laser applications.

Contribution

It introduces a high-power quasi-CW thulium-doped fiber laser with detailed performance metrics and thermal advantages, advancing pulsed fiber laser technology.

Findings

Achieved 198 W instantaneous power in 0.2-ms pulses at 50 Hz

Slope efficiency of 67% up to 200 W absorbed pump power

Low duty cycle simplifies heatsinking despite high thermal load

Abstract

A thulium-doped fiber laser operating quasi-continuous-wave generated 198 W of instantaneous output power in 0.2-ms pulses at 50 Hz repetition rate. The duty cycle becomes 1% and the average output power 2.0 W. This was cladding-pumped with 408 W from 0.79-um diode lasers (average pump power 4.1 W). The pump switch-on time was ~10 us at full power, with the laser exhibiting relaxation oscillations starting ~5 us after the start of the pumping and lasting for ~5 us. The slope efficiency with respect to absorbed pump power was 67% up to 200 W of absorbed pump power and 52% at the full 352 W of absorbed pump power. The low duty cycle simplified the heatsinking, despite the high instantaneous power and thermal load.