We demonstrate tunable mid-infrared (MIR) Raman soliton generation in an all-solid fluorotellurite fiber pumped by a 1960 nm femtosecond fiber laser. All-solid fluorotellurite fibers are fabricated by using a rod-in-tube method. The core and cladding materials are TeO₂-BaF₂-Y₂O₃ (TBY) and AlF₃-based glasses. Since the refractive index of AlF₃-based glass is much lower than that of TBY glass, the zero-dispersion wavelength of all-solid fluorotellurite fiber can be tuned in a wide range by simply varying the core diameter of the fiber. By using a 0.5 m long all-solid fluorotellurite fiber with a core diameter of ∼ 2.7 μm as the nonlinear medium and a 1960 nm femtosecond fiber laser as the pump source, tunable MIR Raman soliton generation from 1.96 to 2.82 μm is obtained via soliton self-frequency shift by increasing the pump power. For the soliton laser source operating at 2.82 μm, the obtained optical-to-optical conversion efficiency is about 18% and the calculated pulse width is about 93 fs. Our results show that all-solid fluorotellurite fibers are promising nonlinear media for constructing tunable MIR ultrafast laser sources.

We propose and demonstrate the generation of optical frequency combs via four-wave mixing in a dual wavelength Brillouin laser cavity. When pumped by two continuous-wave lasers with a varied frequency separation, dual wavelength Brillouin lasers with reduced linewidth and improved optical signal to noise ratios are generated in a direction opposite to the pump laser. Simultaneously, cavity-enhanced cascaded four-wave mixing between dual wavelength Brillouin lasers occurs in the laser cavity, causing the generation of broadband optical frequency combs with step tunable mode spacing from 40 to 1300 GHz. Compared to the cavity-less case, the number of the comb lines generated in the dual wavelength Brillouin laser cavity is increased by ∼38 times.

We demonstrated broadband S-band (1460–1530 nm) amplification in Tm³⁺-doped fluorotellurite glass fibers (TDFTFs) by using a 1400/1570 nm dual-wavelength pump technique. TDFTFs based on TeO₂-BaF₂-Y₂O₃ (TBY) glass were fabricated by using a rod-in-tube method. For an input signal power of 0 dBm (or 1 mW), a broadband positive net gain ranging from 20 dB was ∼66 nm (1458–1524 nm), and the measured saturated output power was ∼24.84 dBm at 1490 nm. In addition, numerical simulation was performed by using the parameters of the TDFTFs and the pump lasers, and the noise figure was calculated to be <5.6 dB in the S band. Our results showed that the TDFTFs were promising gain media for constructing efficient broadband S-band fiber amplifiers.

Fluoroindate glass fibers with an E r 3 + doping concentration of ∼ 0.5 m o l % were fabricated by using a rod-in-tube method. Pumped by a 976 nm laser diode, intense emission at ∼ 3.3 µ m was obtained from a 40 cm long E r 3 + -doped fiber, which could be attributed to the transition 4 S 3 / 2 → 4 F 9 / 2 of E r 3 + ions. The calculated emission cross section at ∼ 3.3 µ m was ∼ 3 × 10 − 26 m 2 , which was ∼ 1.5 times larger than that of transitions E r 3 + : 4 F 9 / 2 → 4 I 9 / 2 and D y 3 + : 6 H 13 / 2 → 6 H 15 / 2 . In addition, broad emissions ranging from 3.1 µm to 3.85 µm were obtained in the E r 3 + -doped fiber under a 976 nm/1973 nm dual-wavelength pumping scheme. Our results indicated that E r 3 + -doped fluoroindate glass fibers had the potential for constructing efficient ∼ 3.3 µ m fiber lasers.

In this letter, we demonstrate a 25.8 W all-fiber mid-infrared supercontinuum (SC) light source based on fluorotellurite fibers. All-solid fluorotellurite fibers are fabricated by using a rod-in-tube method. A 56 cm long fluorotellurite fiber with a core diameter of $\sim 11~\mu \text{m}$ is used as the nonlinear medium and a high power $1.93\sim 2.5~\mu \text{m}$ SC fiber laser as the pump source. The fluorotellurite fiber is connected to the output silica fiber of the pump source by direct fusion splicing, leading to the formation of the compact all-fiber structure. For a pump power of ~42.6 W, we obtain a 25.8 W SC light source with a spectral range from 0.93 to 3.99 $\mu \text{m}$ . The corresponding optical-to-optical conversion efficiency is about 60.6%. To the best of our knowledge, this is the first time to report all-fiber high power mid-infrared SC light source based on fluorotellurite fibers. Our results pave the way to apply mid-infrared SC light sources based on fluorotellurite fibers for real applications.