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Mid‐infrared (MIR) band supercontinuum (SC) light source has highly important application prospects in aerospace, biomedicine, MIR sensing, and pollutant monitoring. As–Se–Te glass has high nonlinear refractive index, wide MIR transmission range and weak crystallization ability. As40Se40Te20 glass fiber is suitable for producing wide MIR–SC spectrum. In this study, purified As40Se40Te20 glass was prepared and unclad and step‐index fibers were drawn. An unclad As40Se40Te20 glass fiber with minimum loss of 1.7 dB/m at 8.8 μm was obtained. By pumping the unclad fiber in the normal dispersion region at 5 μm, we recorded the broadest SC generation spectrum, which covered 1.8–13 μm with a 30 dB spectral flatness, from a fiber with 15 cm length. Besides, As40Se40Te20/As40Se42Te18 step‐index fiber with minimum loss of 5.6 dB/m at 5 μm was drawn from isolation extruded preform. The step‐index fiber was pumped in the normal dispersion region at 5 μm, and the SC spectrum, covering 2.1–11.2 μm with a 40 dB spectral flatness, was recorded from a fiber with 15 cm length. The SC spectrum, which was achieved by pumping the As40Se40Te20 fiber, covered almost all the transparent range of material. [ABSTRACT FROM AUTHOR]

A combined infrared suspended-core fiber (SCF) is fabricated using a stacked glass extrusion method. As2S 3 glass is used as the center core host material, and Ge20As20Se15Te45 glass is used to form supporting bridges and act as the ring host material. In this paper, a continuous and robust extrusion process was used to fabricate the SCFs on stacked chalcogenide glass substrates. Glass flow disruption and shear band formation at the interfaces between the different glasses were avoided while the suspended core was formed directly from the core glass. The near-field optical energy distribution image of the resulting multimaterial SCF shows that light propagates effectively in the core. The losses of the multimaterial SCF were also measured at wavelengths ranging between 2.5 and 7 μm, and the lowest transmission loss was 1.86 dB/m at 4.8 μm. The spectral behavior of the supercontinuum (SC) in the SCF is investigated by varying the pump wavelength and the pump power. A mid-infrared SC spanning a wavelength range from 2.05 to 6.95 μm is generated in a 19-cm-long combined chalcogenide SCF that is pumped at 4.5 μm using an optical parametric amplifier laser system. [ABSTRACT FROM AUTHOR]

Fibers exhibiting flattened and decreasing dispersion are important in nonlinear applications. Such fibers are difficult to design, particularly in soft glass. In this work, we develop a preliminary design of a highly nonlinear tapered hybrid microstructured optical fiber (TH-MOF) with chalcogenide glass core and tellurite glass microstructure cladding. We then numerically studied its dispersion, loss, and nonlinearity-related optical properties under fundamental mode systematically using the infinitesimal method. The designed TH-MOF exhibits low chromatic dispersion that is similar to a convex function with two zero-dispersion wavelengths and decreases with fiber length from 2 to 5 μm band. The potential use of the TH-MOF in nonlinear applications is demonstrated numerically by a supercontinuum spectrum of 20 dB bandwidth covering 1.96–4.76 μm generated in 2-cm-long TH-MOF using near 3.25-μm fs-laser pump. [ABSTRACT FROM PUBLISHER]

Compared with the traditional fluoride fibers and tellurite fibers that can work in the near-infrared region, suspended-core fibers based on chalcogenide glasses have wider transmitting regions and higher nonlinear coefficients, thus the mid-infrared supercontinuum generations can be achieved easily. Rather than adopting the traditional fabrication technique of hole-drilling and air filling, we adopted a totally novel extrusion technique to fabricate As2S3 suspended-core fibers with four holes, and its mid-infrared supercontinuum generation was investigated systematically by integrating theoretical simulation and empirical results. The generalized nonlinear SchrÖdinger equation was used to simulate the supercontinuum generation in the As2S3 suspended-core fibers. The simulated supercontinuum generation in the As2S3 suspended-core fibers with different pump wavelengths (2-5 µm), increasing powers (0.3-4 kW), and various fiber lengths (1-50 cm) was obtained by a simulative software, MATLAB. The experimental results of supercontinuum generation via femtosecond optical parametric amplification (OPA) were recorded by changing fiber lengths (5-25 cm), pump wavelengths (2.9-5 µm), and pump powers (10-200 kW). The simulated consulting spectra are consistent with the experimental results of supercontinuum generation only if the fiber loss is sufficiently low. [ABSTRACT FROM AUTHOR]

A Co2+:ZnS-doped chalcogenide glass with broadband mid-infrared emission was prepared by using a hot uniaxial pressing process. The refractive index difference (Δn) between matrix glass (As 2 S 5) and crystal (Co2+:ZnS) was controlled to be 0.0042 in the emission spectral range of Co2+ to minimize the scattering effect. An ultrabroadband mid-infrared emission of 2–4 μm was observed at room temperature in the samples after excitation by using a commercially available laser diode of 1550 nm. The significant changes in the lifetime and fluorescence intensity of Co2+:ZnS-doped chalcogenide glass were measured in the temperature range of 90–290 K. A resolution of approximately 0.18 K was observed when used as a temperature detector. Furthermore, a gas-sensing device was built by using the strong and broad emissions of the sample, and the detection sensitivity of butane reached 56 ppm. These results show that this glass-ceramics can be used as optical sensing of gas and temperature. [ABSTRACT FROM AUTHOR]

Abstract High quality large-core As Se chalcogenide fiber was fabricated via a novel extrusion method to peel off the out-layer of the core glass, and thus all the defects, such as deformations, interface bubbles between the core and cladding can be eliminated effectively. The raw materials were purified by the dynamic distilling and the glasses were prepared by the melt-quenching method. The preform was prepared by an improved isolated stacked homemade extrusion (ISE) machine. The fibers coated with polymer protection were drawn out with a core diameter of ∼240 μm. The core/cladding ratio of the fiber were kept approximately 1:2, and the optical loss was generally lower than 1.5 dB/m in a wavelength range of 5.6–9.7 μm, with a minimum value of 0.6 dB/m at 8.3 μm. The calculated fiber numerical aperture was approximately 0.55. Supercontinuum (SC) generation experiments of fiber at different wavelengths and pump powers were performed. A flattened SC spectrum can be obtained in this large-core fiber with femtosecond pumping. Highlights • A peeled-off extrusion technique was presented for chalcogenide glass fiber. • This step-index As-Se fiber shows a low optical loss in midinfrared with a minimum value of 0.6 dB/m at 8.3 μm. • A flatness supercontinuum spectrum covering 1.5-13.3 μm can be obtained in this As-Se fiber pumped with a femtosecond laser. [ABSTRACT FROM AUTHOR]

We report a broadband supercontinuum generation in a chalcogenide fiber taper with an ultra-high numerical aperture. The chalcogenide step-index fiber consisting of As 2 Se 3 core and As 2 S 3 cladding was fabricated by using the isolated stacked extrusion method. The fiber taper with a core diameter of 1.75 μm was prepared by employing a homemade tapering setup. By pumping the fiber taper with a femtosecond laser pulses at 3.3 μm, a broadband supercontinuum generation spanning from 1.9 to 5.7 μm was achieved. [ABSTRACT FROM AUTHOR]

We report broadband supercontinuum (SC) spectra generated from low-loss single-mode fibers (SMF) based on novel Ge–As–S–Se (GASS) chalcogenide (ChGs) glasses. The step-index fibers (SIF) possess an ultra-low background loss of 0.27 dB/m at wavelength of 2.5 ∼ 7. 5 μ m were fabricated by an optimized peeled-off extrusion method. SC generation was studied by pumping the fiber with 15 cm and 100 cm at same condition (5 μ m, ∼ 150 fs, 1 kHz, 25 mW), respectively. Output SC covering 1.46 ∼ 9. 32 μ m was obtained in this 15-cm fiber, while a relatively wide output SC spanning from 1.68 to 8. 28 μ m was observed in 100-cm fiber. Due to simulated numerical model does not account for higher-order modes at shorter wavelengths, cladding modes, polarization effects etc. Experimental SC spectral profile in the short and long S/Se fibers is slightly different with the simulation analysis. To the best of our knowledge, this is the first report on the performance of GASS fiber. • The fiber with an ultra-low background loss of 0.27 dB/m in 2.5 ∼ 7. 5 μ m. • SC spectrum covering 1.46–9.32 μ m was obtained in a 15 cm fiber, 1.68–8.28 μ m for 100 cm. • This fiber was better than As 2 S 3 fiber in operating window and higher damage than As 2 Se 3. [ABSTRACT FROM AUTHOR]

• Arsenic-free low-loss fiber was fabricated by a process of peeled-off extrusion. • The fiber exhibits a minimum optical loss of 0.87 dB/m at 5.1 μm. • The broadest spectrum from 1.56 to 7.59 μm at −30 dB was achieved successfully. A low-loss and Arsenic-free sulfur-based chalcogenide fiber(Ge-Sb-S) was fabricated by a novel process of peeled-off extrusion. The fiber has an optical loss of <2 dB/m in a range from 5 to 6 μm with a minimum loss of 0.87 dB/m at 5.1 μm. A mid-infrared (MIR) supercontinuum (SC) spectrum covering 1.56–7.59 μm was generated from a 22-cm long fiber pumped with a femtosecond laser at 4 μm (−150 fs, 1 kHz). Simultaneously, we demonstrated that the optical fiber has a transmission efficiency of 53% at 4 μm, which is the key significance for applications such as IR night vision, bio-photonics, military defense and environmentally friendly industry. [ABSTRACT FROM AUTHOR]

Chalcogenide glass fiber usually possesses a single zero-dispersion wavelength (ZDW) that is more than 5 µm. Here, a novel W-typed double cladding chalcogenide glass fiber was designed and fabricated with optimized dispersion properties based on As 2 Se 3 -Ge 7 As 23 S 70 -Ge 10 As 23 Se 67 glasses. The results show that there are two ZDWs locating at near-infrared 2.95 µm and far-infrared 11.77 µm, and the dispersion less than 8 ps/km/nm at this range. Based on numerical simulation and viscosity analysis, a novel W-typed double-cladding fiber is fabricated via extrusion method, and the lowest loss of 1.15 dB/m is obtained at 5.68 µm. The optimized structure and dispersion distribution of the fiber ensure the excellent supercontinuum generation. When pumping at 3 µm near the first ZDW, a bandwidth supercontinuum (SC) spanning from 1 to 10.9 µm can be obtained. By pumping at 5 µm, a broad bandwidth of SC output from 1.3 to 13 µm can be obtained. This kind of low ZDW fiber has great potential for the generation of supercontinuum in the future. [ABSTRACT FROM AUTHOR]

• A dual-clad step-index chalcogenide fiber based on tellurium glasses was proposed and investigated detailedly for midinfrared coherent supercontinuum generation. • The structure of the fiber with a W-type refractive-index profile was numerically studied and optimized for all-normal dispersion profile. • Due to the large material zero dispersion wavelength, an all-normal dispersion tellurium chalcogenide fiber was realized via the waveguide chromatic engineering. • The optimized fiber was fabricated via extrusion and employed for coherent supercontinuum generation. • The result shows that a high coherent supercontinuum covering 3.5–10.5 μm can be generated in this fiber with 5 μm femtosecond laser pumping. • This is the first numerical investigation on the dispersion engineering of tellurium chalcogenide dual-clad step-index fiber. Considerable investigations have been carried out for chromatic dispersion tailoring of chalcogenide glass fiber with various structures and different material compositions. Here we proposed a tellurium-based chalcogenide glass fiber with a dual-clad structure in a W-type refractive-index profile. The structure of the fiber based on Ge-As-Se-Te glasses was numerically analyzed in detail. The simulation results indicate that an all normal dispersion profile can be realized in this tellurium glass fiber with an optimized dual-cladding structure. Then the optimized tellurium chalcogenide fiber with an all-normal dispersion profile was fabricated by multi-extrusion method. Pumping with a 5 μm ultra-short pulsed laser (150 fs, 1 kHz), abroadband supercontinuum (SC) covering 1.5–11 μm can be generated in the 19 cm-long fiber. The coherence of SC was also investigated by numerical simulation. The result shows that a high coherent SC covering 3.5–10.5 μm can be generated in this all-normal dispersion fiber. In conclusion, all-normal dispersion profile can be realized easily in this tellurium-based glass fiber due to their large materials ZDWs. [ABSTRACT FROM AUTHOR]