Transmission spectrum alteration of a silica fiber taper while covering lateral surface with heterostructure of ZnTe/Bi₂Te₃ thin film

Abstract

Short tapered fiber sections 3-10 mm in length and 12-20 microns in diameter were fabricated through the partial etch removal of the outer silica cladding. ZnTe and Bi 2 Te 3 crystalline films 1-60 nm thick were subsequently applied to the surface of the tapered fiber sections using metalorganic chemical vapor deposition. Transmission spectra of the taper were recorded within the wavelength region of 1-1.6 μm at regular intervals whilst the deposition. Strong decreases in transmission in relatively narrow spectral bands were observed. The results can be applied to lossy mode resonance fiber sensors and passively mode-locked pulsed fiber laser designs.

Sensitivity of lossy mode resonance-based optical fiber sensors as a function of the coating material refractive index

“…In this work, a well-known approach to calculate the parameters of a dielectric light guide, in the transmission spectrum of which a LMR can be detected, was used [25,26]. The finite element method (FEM) was exploited to compute the imaginary and real parts of the effective refractive index n eff of the core and cladding modes of a cylindrical light guide with a diameter of 18 μm and a length of 4 mm, coated with a thin film (thickness < 2 μm) with a real part of the refractive index from 1.7 to 3.4.…”

“…In the case of interplay with the TE and TM modes of a thin film, TE and TM LMRs are observed in the transmission spectrum of a dielectric waveguide, respectively. The geometric parameters of the dielectric waveguide were selected based on their values used in practice [19,25,27,28]. The studied structures are often made by depositing a semiconductor or dielectric coating on the region of a standard singlemode optical fiber (SMF-28) that is thinned by chemical etching.…”

“…It is known that the position of the resonance does not depend on the imaginary part of the refractive index of the coating [40], so this value was chosen for the following reasons. First, theoretical estimates based on the transmission spectra of fiber-optic tapers coated with ZnTe [25,26], and second, the conditions that the transmittance (T = 100 • e −4π•Im(n eff )•L/λ , where L-taper length, λ-wavelength) of the calculated modes where this quantity coincides for the superior and inferior modes for all coating materials is in the range from 10 to 90%. This band is the most convenient from a practical point of view.…”

Fabrication and Applications of Heterostructure Materials for Broadband Ultrafast Photonics

“…In 2019, Kuznetsov et al used the MOCVD method to create a kind of heterostructure to cover the lateral surface of a tapered fiber. [93] They found that monolithic crystalline films of Bi 2 Te 3 could be deposited onto the surface of various dielectrics by MOCVD after a buffer layer like ZnTe is deposited. After 30 s of interruption, other reactants were injected into the chamber for the deposition of Bi 2 Te 3 films.…”

MOCVD deposition of zinc and bismuth chalcogenides films on the surface of silica optical fibres

“…ZnSe has conductivity of an electronic type, and ZnTe has a hole-type conductivity. Due to the ability of in situ recording of the optical transmittance spectra during the deposition of semiconductor films by MOCVD on tapered silica fibres [6], it is possible to control the spectral position, shape, depth and width of the LMR line.…”