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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. [ABSTRACT FROM AUTHOR]

We demonstrate a stable spacing-adjustable multi-wavelength erbium-doped fiber laser by employing an adjustable fiber Michelson interferometer. The central wavelength of the multi-wavelength laser can be tuned by adjusting the polarization controllers, while the wavelength spacing can be continuously tuned by adjusting the optical delay line in the Michelson interferometer. Tunable wavelength spacing is achieved in the range of 0.045 to 0.7 nm. More than 60 wavelengths within a flatness of 3 dB and wavelength spacing of 0.0474 nm can be achieved. [ABSTRACT FROM AUTHOR]

We demonstrate supercontinuum (SC) generation in a 2.8-cm-long chalcogenide double-clad fiber (Ch-DCF). The calculated chromatic dispersion of the fundamental mode shows that the Ch-DCF has flattened chromatic dispersion, which is within −10 ± 10 ps/nm/km from 3.8 to 12.6 in the normal dispersion regime. The variation of SC spectra is investigated by changing the pump wavelength and pump peak power. The broadband SC spectra extending from 2 to 14 μm at the −40 dB level is observed when the pump wavelength of 10 μm and pump peak power of 1.3 MW. The SC generation is simulated by the scalar generalized nonlinear Schrödinger equation. The simulation results are mostly the same as the experimental results and show that the supercontinua generated in the Ch-DCF are highly coherent. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We demonstrate the supercontinuum (SC) generation in a chalcogenide step-index fiber with AsSe2 core and As2S5 cladding. The characteristics of fiber are analyzed using the full-vectorial mode solver technique. The fiber has two zero-dispersion wavelengths at 2898 and 5140 nm. The evolving of SC spectra with fiber length and pump wavelength is investigated experimentally. The maximum SC range covering one octave from 1550 to 3300 nm is obtained when the 20 cm long fiber is pumped by 2000 nm pulses in normal dispersion region. The fiber can push forward the nonlinear application based on the stimulated Raman effect, stimulated Brillouin effect, four-wave mixing, supercontinuum generation, and so on in the mid-infrared waveband. The SCs are simulated by the nonlinear Schrödinger equation. The simulated results agree well with the experiments. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The evolution of mid-infrared (MIR) higher-order soliton fission in a tapered tellurite microstructured optical fiber (TMOF) is experimentally investigated. From ∼30 to 80 mW, the redshift of the first fundamental soliton is obvious. From ∼80 to 120 mW, two fundamental solitons are obtained by the fission of higher-order solitons. The redshift of the first fundamental soliton almost stops because the increased pump power is preferentially distributed to the second fundamental soliton. From ∼120 to 180 mW, an obvious redshift of the first fundamental soliton is observed again, and a third fundamental soliton is obtained at ∼180 mW. The evolution of each soliton is determined by the power distribution, which is, to the best of our knowledge, reported for the first time. [ABSTRACT FROM AUTHOR]

A broadband fibre-optical parametric amplifier (FOPA) operating at a novel wavelength region that is far from the pump wavelength has been demonstrated by exploiting two pairs of adjacent four-wave mixing (FWM) sidebands generated simultaneously in a tellurite microstructured optical fibre (TMOF). Owing to the large nonlinearity of the TMOF and the high pump peak power provided by a picosecond laser, a maximal average gain of 65.1 dB has been obtained. When the FOPA is operated in a saturated state, a flat-gain amplification from 1424 nm to 1459 nm can be achieved. This broadband and high-gain FOPA operating at new wavelength regions far from the pump offers the prospect of all-optical signal processing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]