Ultralow-loss fusion splicing between negative curvature hollow-core fibers and conventional SMFs with a reverse-tapering method.

Caoyuan Wang,Limin Xiao,Benoît Debord,Fetah Benabid,Ruowei Yu,Frédéric Gérôme,Kin Seng Chiang

doi:10.1364/oe.432147

Abstract

Negative curvature hollow-core fibers (NC-HCFs) can boost the excellent performance of HCFs in terms of propagation loss, nonlinearity, and latency, while retaining large core and delicate cladding structures, which makes them distinctly different from conventional fibers. Construction of low-loss all-fiber NC-HCF architecture with conventional single-mode fibers (SMFs) is important for various applications. Here we demonstrate an efficient and reliable fusion splicing method to achieve low-loss connection between a NC-HCF and a conventional SMF. By controlling the mode-field profile of the SMF with a two-step reverse-tapering method, we realize a record-low insertion loss of 0.88 dB for a SMF/NC-HCF/SMF chain at 1310 nm. Our method is simple, effective, and reliable, compared with those methods that rely on intermediate bridging elements, such as graded-index fibers, and can greatly facilitate the integration of NC-HCFs and promote more advanced applications with such fibers.

Highlights

A hollow-core fiber (HCF), an optical fiber with a hollow core surrounded by a microstructured cladding, exhibits the ability to guide light in air, which enables a wide range of new applications [1,2,3,4,5,6,7,8,9,10,11,12]
Zheng et al [15] have demonstrated that a Negative curvature hollow-core fibers (NC-HCFs) can be precisely tapered without destroying its delicate core-contour negative curvature, and they have achieved a splicing loss of 0.48 dB measured from the single-mode fibers (SMFs) to the NC-HCF and a reverse splicing loss of 3.5 dB at 1550 nm
Our method allows the mode area and the mode-field distribution of a conventional SMF to be precisely controlled to match those of the NC-HCF

Summary

Introduction

A hollow-core fiber (HCF), an optical fiber with a hollow core surrounded by a microstructured cladding, exhibits the ability to guide light in air, which enables a wide range of new applications [1,2,3,4,5,6,7,8,9,10,11,12]. Zheng et al [15] have demonstrated that a NC-HCF can be precisely tapered without destroying its delicate core-contour negative curvature, and they have achieved a splicing loss of 0.48 dB measured from the SMF to the NC-HCF and a reverse splicing loss of 3.5 dB at 1550 nm In these two methods, the reverse coupling losses are much larger, because the high-order modes excited in the NC-HCF create large coupling losses to the SMF. It remains a challenge to develop a highly repeatable fusion splicing process for the construction of low-loss all-fiber NC-HCF links

Methods

Results

Conclusion