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We demonstrate a coherent mid-infrared supercontinuum generation in a step-index tellurite fiber with an all-normal dispersion profile. A coherent supercontinuum spectrum spanning 1340–2840 nm in a 6.3-cm-long tellurite step-index fiber is obtained when the fiber is pumped with 200 fs laser pulses with a coupled peak power of 5.5 kW at 2000 nm. Such fiber-based coherent mid-infrared supercontinuum sources are highly required for the imaging of biological tissues in optical coherence tomography, pump–probe spectroscopy, pulse compression, and sensing.

We experimentally demonstrate mid-infrared (MIR) supercontinuum (SC) generation in a 2.8-cm-long chalcogenide double-clad fiber (Ch-DCF). The Ch-DCF made of As2Se3, AsSe2, and As2S5 glasses has near-zero chromatic dispersion in the normal dispersion regime. We pump the Ch-DCF using a 200 fs pulse laser at 10 µm, and obtain MIR SC extending from 2 to 14 µm. Numerical results show that the Ch-DCF has the potential of generating a highly coherent MIR SC light source.

Wavelength-tunable picosecond degenerate four-wave mixing was demonstrated in a tellurite microstructured optical fiber (TMOF). The zero-dispersion wavelength of the TMOF was shifted to 1570 nm by introducing a single ring of air holes in the cladding. The anti-Stokes signal sideband can be generated from 1490 to 1500 nm, and the Stokes idler sideband can emit from 1595 to 1645 nm. Because of the high nonlinearity of the TMOF and the large peak power of the picosecond pump, a maximal signal gain of 31.2 dB and an idler conversion efficiency of +35 dB were achieved.

We design and fabricate an all-solid chalcogenide microstructured optical fiber (MOF) with four rods in the cladding, in order to generate mid-infrared (MIR) dispersive waves (DWs). The high-index background is made of AsSe2 glass, and the four low-index rods are made of As2S5 glass. This MOF has two zero-dispersive wavelengths: ∼3,720 and 4,230 nm. The propagation loss is ∼1.9 dB/m at 2,000 nm, and the nonlinear coefficient is ∼4 × 103 km−1 W−1 at 3,000 nm. Using a pulse of ∼80 MHz and ∼200 fs emitted from an optical parametric oscillator as the pump source, the resulting MIR DWs are investigated at different pump wavelengths.

An ultra-broadband supercontinuum (SC) covering 0.2–8.0 µm which is more than 5 octaves, is demonstrated in a piece of fluoride glass. The 20 dB bandwidth spans from 0.39 to 7.4 µm. The filaments, bright conic visible emission, and interference fringe pattern are observed. The glass thickness, optical path, and pump conditions are optimized to enable the SC to cover the entire transmission range of the glass, which includes the whole functional group region of chemical bands and groups. The SC conversion efficiency is confirmed to be stable.

In this paper, we present a new way of enhancing the Stimulated Brillouin scattering (SBS) of higher-order acoustic modes in the four-core tellurite (TZLB) microstructured optical fiber (MOF). The Brillouin gain spectrum (BGS) in the MOF is calculated based on a full model analysis of the optical and acoustic properties. In contradict to the single-core tellurite MOF, BGS of the four-core tellurite MOF has three peaks, which are contributed by the fundamental and higher-order acoustic modes. The higher-order acoustic modes can enhance the interaction with the optical mode and provide a strong contribution to the Brillouin response.

Tb3+/Yb3+ codoped KY3F10 nanocrystals with the average size of 45 nm were synthesized using a facile hydrothermal method. Under the excitation by a 976 nm laser, the codoped samples exhibited intense ultraviolet (5D3 → 7F6) and blue upconversion emissions (5D3 → 7F5) from Tb3+ ions. It was observed for the first time that the intense ultraviolet emission was two times stronger than the green emission of Tb3+, which was about 100 times stronger than the results previously reported. The upconversion mechanism was investigated based on the energy transfer from Yb3+ to Tb3+ and the cross-relaxation process between Tb3+ pairs.

We report the fabrication of tellurite composite microstructured optical fibers (CMOFs) which consist of a TeO2–Li2O–WO3–MoO3–Nb2O5 (TLWMN) tellurite glass core and TeO2–ZnO–Na2O–La2O3 (TZNL) tellurite glass cladding. Flattened chromatic dispersion and tunable zero dispersion wavelength (ZDW) were realized in the small core diameter (~1.5 µm) fiber with six surrounding air holes. The optical loss was measured to be about 4.0 dB/m in the spectral range of 1510–1640 nm. Supercontinuum (SC) generation was demonstrated by a femtosecond laser pumping at 1.55 µm. The threshold pump power for this novel tellurite CMOF was the lowest among tellurite microstructured optical fibers (MOFs).

Transparent glass-ceramics containing YLiF4 nano-crystals were synthesized by controlled heat treatment of LiF–YF3–Al2O3–SiO2 glass. The crystallite size, estimated to be about 8 nm, was much less than the wavelength of visible light. From the fluorescent properties of the Er3+-doped precursor glass and the glass-ceramic, it was confirmed that Er3+ could be incorporated into YLiF4 nano-crystallites in the glass-ceramic. This transparent glass-ceramic containing YLiF4 nano-crystals is promising as a gain medium for rare earth-doped fiber lasers and amplifiers.

Organic–inorganic hybrid transparent materials containing nickel ion-doped magnesia (Ni:MgO) nano-crystals are investigated as gain media. Thin films and bulk samples are prepared by a sol–gel technique. Starting sols for host matrices, which are prepared from diphenyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and titanium tetra-n-butoxide, are mixed ultrasonically with flame spray made Ni:MgO nano-crystals ultrasonically. The hybrid materials containing Ni:MgO nano-crystals with high transparency are realized by matching refractive indices of the host matrices with that of Ni:MgO by controlling starting sols' composition. A broad emission centered at 1330 nm is confirmed under the excitation at 976 nm.