A Dual Hollow Core Antiresonant Optical Fiber Coupler Based on a Highly Birefringent Structure-Numerical Design and Analysis

Abstract

With the growing interest in hollow-core antiresonant fibers (HC-ARF), attributed to the development of their fabrication technology, the appearance of more sophisticated structures is understandable. One of the recently advancing concepts is that of dual hollow-core antiresonant fibers, which have the potential to be used as optical fiber couplers. In the following paper, a design of a dual hollow-core antiresonant fiber (DHC-ARF) acting as a polarization fiber coupler is presented. The structure is based on a highly birefringent hollow-core fiber design, which is proven to be a promising solution for the purpose of propagation of polarized signals. The design of an optimized DHC-ARF with asymmetrical cores is proposed, together with analysis of its essential coupling parameters, such as the extinction ratio, coupling length ratio, and coupling strength. The latter two for the x- and y-polarized signals were ~2 and 1, respectively, while the optical losses were below 0.3 dB/cm in the 1500–1700 nm transmission band.

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

“…The structure of the previously presented DHCARF is rather complicated due to the presence of elliptical capillaries [39]. HCARFs with such capillaries have not been fabricated up to this date, which can be a result of two factors.…”

“…The value of w 1 was calculated directly from Equation (1), while w 2 was swept for different values in order to obtain proper CLR. The complete procedure of using w 1 and w 2 (as well as the other geometrical parameters) to modify the DHC-ARF's optical parameters is described in detail in [39]. In short, two types of capillaries (thick and thin ones, described by w 1 and w 2 , respectively) have effectively made the proposed structure birefringent.…”

“…A potential optical device which could allow one to perform multiphoton FA in a completely fiberized manner would be a dual hollow-core antiresonant fiber (DHC-ARF). The idea of splitting signals with different polarizations using DHC-ARF structures has only been analyzed theoretically so far in terms of their optical and geometrical properties [38,39]. However, according to the authors' best knowledge, no results have been reported where a DHC-ARF (or any other kind of dual-core fiber) was used in a fluorescence anisotropy detection setup, with the fiber being the main part of the sensor.…”

“…In this paper, we present a theoretical investigation of a DHC-ARF-based fluorescence anisotropy sensor. Based on our experience from previous work [39], we propose a DHC-ARF with a structure comprising only circular-shaped capillaries. The structure has been designed to allow for an efficient transmission of signals from the NIR (Near-Infrared) and VIS (Visible) wavelengths region, hence being a viable solution for multiphoton excited fluorescence experiments.…”

Fibre devices enabled by hollow core fibre technology

“…The advances in HC-PCF design and fabrication have been encouraging investigation into the HC-PCF based components and devices. The multi-core HC-PCFs (MHCFs) have appealed to the researchers, for their potential to serve as coupler, interferometer, mode filter, and polariser [65][66][67]. The exploration of the MHCF components could benefit the current fibre components with the advantages HC-PCFs and the integration of the HC-PCFs into all-fibre systems.…”