Chalcogenide Taper and Its Nonlinear Effects and Sensing Applications

Abstract

The nonlinear coefficient of chalcogenide glass is 200-1000 times larger than that of silica glass, and it is transparent in the 1-15 mm wavelength windows, which makes the nonlinear effects happen at much low power with a short length in near-and mid-infrared wavelength window. With tapered chalcogenide fibers, the power density in the core and the waveguide nonlinearity can be enhanced to make nonlinear signal processing unit at a compact size. The threshold of Raman scattering and supercontinuum generation is reduced due to the enhanced Kerr effect and enhanced optical power intensity. Phase-matching condition required in four-wave mixing (FWM) can be realized by tailoring fiber structures to engineer the chromatic dispersion, which enables new wavelengths creation over a large range at mW power and sub-meter length. The guided acoustic waves and longitudinal acoustic waves can be generated and detected in mW power with chalcogenide tapers. The high power density in the microwires and the high photosensitivity of chalcogenide glass in the 1550 nm band enable the inscription of FBGs in the fiber directly. The chalcogenide microwires are fragile and the core diameter cannot be tapered down to sub-microns, which can be mitigated by polymer coating that can provide mechanical strength. Polymers not only provide high mechanical strength as the coating and cladding materials but also bring over 10 times larger thermal expansion than chalcogenide cores, which enhances the sensor prospect of the chalcogenide fibers for temperature, strain, and acoustic sensing. This work reviews the present and emerging trends in investigation of chalcogenide tapers, mainly focusing on the fabrication procedure of chalcogenide microwires, the nonlinear effects, and sensing applications.

Optimization of different temperature annealed nanostructured CdSe thin film for photodetector applications

“…The polarization of the material system is expressed in terms of nonlinearity and well evaluated by utilizing semi-empirical relations involving the film's refractive indices. The 3 rd order nonlinear optical susceptibility ( (3) ) is an important factor that decides the of use of a particular material in nonlinear photonic devices [33]. The nonlinear refractive index '𝑛 2' is the material's disproportionate response to the applied electric field.…”

Exploring the Optical Bound State in the Continuum in a Dielectric Grating Coupled Plasmonic Hybrid System

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Optimization of Different Temperature Annealed Nanostructured CdSe Thin Film for Photodetector Applications

“…The polarization of the material system is expressed in terms of nonlinearity and well evaluated by utilizing semi-empirical relations involving the film's refractive indices. The 3 rd order nonlinear optical susceptibility ( (3) ) is an important factor that decides the of use of a particular material in nonlinear photonic devices [33]. The nonlinear refractive index ' 2' is the material's disproportionate response to the applied electric field.…”