Generation of sub-150†fs, 10†W-class, pedestal-free 2.07†µm ultrashort pulses using a cascade compression system.

We report high-power pedestal-free ultrashort pulses in a cascade compression system. In the self-compression stage, the 2 µm ultrashort pulses with 123 fs duration and up to 21.7 W output power were obtained in a 0.3 m 50 µm core diameter fiber. It is the highest self-compressing power ever obtained in a silica fiber with an all-fiber 2 µm laser amplifier as the pump source. To obtain purer pedestal-eliminated pulses, we further increase the fiber length to 1 m to trigger the soliton self-frequency shifting (SSFS) effect. By employing an enhanced SSFS technique based on third-order dispersion (TOD) and filtering out the unshifted signal light, we finally achieved sub-150 fs, 10 W-class, 1.2-MW peak-power, pedestal-free 2.07 µm ultrashort pulses. This is also the highest, to the best of our knowledge, power and energy of Raman soliton obtained by SSFS in an ordinary silica fiber.

High-power tunable Raman soliton generation in large core diameter passive fibers via a precise fundamental-mode matching technique.

We demonstrate tunable high-power, high-energy Raman solitons with the range of 1.9-2.3 µm in large mode area (LMA) fibers and an optimized fundamental-mode matching technique for coupling LMA silica fibers. Finally, we obtained Raman solitons with a maximum output power of 5.8 W and a maximum pulse energy of 105 nJ in a LMA passive fiber with 32 µm core diameter, the tuning range of Raman soliton is 1.96-2.35 µm. In addition, we obtained Raman solitons with a maximum output power of 7.3 W and a maximum pulse energy of 126 nJ in a LMA passive fiber with 48 µm core diameter, the tuning range of Raman soliton is 1.96-2.27 µm. The output power of 7.3 W is the highest Raman soliton power currently available in silica fibers, and the result fills a gap in the generation of both high-power and high-energy Raman solitons in a LMA silica fiber.

All-fiber high-power supercontinuum laser source over 3.5 µm based on a germania-core fiber.

In this Letter, a high-power all-fiber mid-infrared (MIR) supercontinuum (SC) laser source based on 9 cm long germania-core fiber (GCF) pumped by a high-power thulium-doped fiber amplifier is presented. As the pump power was set as 60 W, we obtained a 21.34 W broadband SC source extending from 1742 to 3512 nm with a slope efficiency of 32.5%. The 10 dB spectral bandwidth was over 1000 nm, spanning 1.97 to 3.04 µm. Furthermore, the numerical simulation of SC generation in GCF was in good agreement with the experimental results. As far as we know, this is the highest average output power over 3.5 µm in GCF based on a MIR SC laser source.