High-efficiency tunable femtosecond solitons generation from 1.9 to 2.35 µm in a thulium-doped fiber amplifier via precise seed-pulse management

Abstract

We demonstrate the tunable Raman femtosecond solitons generation with a record-breaking power of 1.2 W at 2.3 µm and an ever-reported highest Raman soliton energy conversion efficiency of 99% via precise seed-pulse management in the thulium-doped single-mode fiber amplifier. We find that the central wavelength and the chirp of the incident pulses could dramatically affect the red-shifted soliton energy, locations, conversion efficiency, and the threshold power in fundamental Raman soliton generation. For the first time, we experimentally illustrated how the seed pulse with Kelly sidebands could affect the Raman solitons generation in this amplifier, and obtained the detailed regularity between the parameters of incident pulses and the properties of the generated solitons. This work provides useful guidance for Raman soliton-based high-power mid-infrared femtosecond laser fabrication.

Soliton Order Preservation for Self-Frequency Shift With High Efficiency and Broad Tunability

“…In contrast to passive fibers, active fibers such as thuliumdoped fiber amplifiers (TDFA), also acting as NLF, have led to SSFS tunability as large as 300 nm while maintaining an ECE as high as 90% [12]- [15]. To enable this, the pump pulse is prechirped prior to SSFS in the TDFA, implemented from an optimized length of dispersion compensating fiber (DCF) [14], [15]. It however remains unclear how pre-chirping acts to enable a broad SSFS tunability while maintaining a high ECE.…”