2.1 m, high-energy dissipative soliton resonance from a holmium-doped fiber laser system

Abstract

We propose a 2.1 μm high energy dissipative soliton resonant (DSR) fiber laser system based on mode-locked seed laser and dual-stage amplifiers. In the seed laser, nonlinear amplifying loop mirror technique is employed to realize mode-locking. The utilization of in-band pump scheme and long gain fiber enables effective exciting 2.1 μm pulses. A section of ultra-high numerical aperture fiber (UHNAF) with normal dispersion and high nonlinearity and an output coupler with large coupling ratio are used to achieve high energy DSR. By optimizing the UHNAF length to 55 m, a 2103.7 nm, 88.1 nJ DSR with a 3-dB spectral bandwidth of 0.48 nm and a pulse width of 17.1 ns is obtained under proper intracavity polarization state and pump power. The output power and conversion efficiency are 0.233 W and 4.57 %, respectively, both an order of magnitude higher than previously reported holmium-doped DSR seed lasers. Thanks to the high output power and