A Method to Process Hollow-Core Anti-Resonant Fibers into Fiber Filters

Abstract

Hollow-Core Anti-Resonant Fiber (HC-ARF) shows promising applications. Nevertheless, there has been a persistent problem when it comes to all-fiber integration due to a lack of HC-ARF-based fiber components. In response to this remaining challenge, we investigate a reliable, versatile and efficient method to convert an HC-ARF into a fiber filter. By locally heating an HC-ARF with a CO2 laser, the fiber structure becomes deformed, and cladding capillaries shrink to produce a thicker wall. This process is analogous to “writing” a new fiber with a thicker wall on the original fiber, resulting in creating new high loss regions in the original transmission bands. Thus, the construction of a fiber filter is realized by “writing” a new fiber on the original fiber. The feasibility of this method is confirmed through experiments, adopting both one- and two-layer HC-ARF. The HC-ARF-based fiber filters are found to have transmission spectra consistent with simulation prediction. Both band pass and band reject fiber filters with more than a 20-dB extinction ratio are obtainable without extra loss. Thus, an in-fiber HC-ARF filter is demonstrated by the CO2 writing process. Its versatile approach promises controlled band selection and would find interesting applications to be discussed.

Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber

“…The diameters of the F2 fiber section are derived from the fact that due to the glass viscosity, under CO 2 laser radiation (or another type of heat processing of the fiber), the capillaries will shrink, while their wall thickness and core diameter will increase. An important feature of introducing such a perturbation is that it can be expected to be fairly uniform [ 29 ].…”

“…Nevertheless, to date, the matter of using NCHCF-based LPGs has not been examined thoroughly. Huang et al managed to convert the NCHCF into an in-line fiber filter [ 29 ] by locally heating an NCHCF with a CO 2 laser and creating a deformation in the NCHCF’s microstructure. In our opinion, a very similar method can be used to write an LPG into an NCHCF.…”

Temperature-Insensitive Mechanical Sensor Using Multi-Modal Behavior of Antiresonant Hollow-Core Fibers

“…We develop a simple method to cause periodic modulation in fiber parameters along a short length (< 1cm) of fiber to achieve this purpose. Our group has reported earlier that subjecting an ARHCF to heat results in thickening of capillary glass walls because of heating and cooling of glass under the effect of surface tension [18]. Therfore, we subjected the FUT to periodic arcs from a commercial splicer (Fujikura FSP 100).…”

Fluorescence Anisotropy Sensor Comprising a Dual Hollow-Core Antiresonant Fiber Polarization Beam Splitter

“…). To take full advantage of their properties, several research groups have begun elaborating other hollow-core fiber-integrated optical devices, such as optical fiber couplers [4,5], filters [6] or sensors [7,8], including multiphoton fluorescence optical fiber sensor setups [9,10]. The latter is a very promising area and is already delivering some remarkable results in biological and medical research by employing not only multiphoton-excited fluorescence but also other non-linear phenomena such as, for example, second harmonic generation or coherent anti-stokes Raman scattering [11,12].…”