High-power, hybrid Er:fiber/Tm:fiber frequency comb source in the 2 {\mu}m wavelength region

TL;DR

This paper introduces a high-power, hybrid Er:fiber/Tm:fiber frequency comb source operating around 2 micrometers, achieving high power and short pulses suitable for various applications.

Contribution

It demonstrates a reliable, high-power hybrid fiber laser system with broadband spectrum generation and femtosecond pulse duration in the 2-micrometer wavelength region.

Findings

Maximum output power of 4.8 W at 1.96 μm

Pulse duration of 141 fs after compression

Coherent broadband spectrum centered at 1.93 μm

Abstract

We present a 2-\mum frequency comb based on a reliable mode-locked Er:fiber laser with 100 MHz repetition rate. After shifting the spectrum of the amplified Er:fiber comb to longer wavelengths, a single-clad Tm/Ho:fiber is used as a self-pumped pre-amplifier to generate a coherent and broadband spectrum centered at 1.93 \mum. Subsequently, a cladding-pumped Tm:fiber amplifier boosts the system to a maximum output power of 4.8 W at 1.96 \mum. After compression in a compact grating compressor, our amplified Er:fiber/Tm:fiber hybrid system delivers as much as 2.9 W with a pulse duration of 141 fs. The system's comb properties are examined via heterodyne measurement.