Ultra-Short Polarization Rotator Based on Flat-Shaped Photonic Crystal Fiber Filled with Liquid Crystal

Abstract

In this study we demonstrate a high-performance polarization rotator (PR) based on flat-shaped photonic crystal fiber. The flat surfaces of the fiber are plated on gold films as electrodes, and the core of the structure is filled with liquid crystal. The polarization rotation characteristics of the flat-shaped fiber can be effectively adjusted by applying external voltage. The optical properties are analyzed using the finite element method (FEM). The results show that the magnitude of the modulation voltage is closely related to the thickness of the flat fiber. When the fiber thickness is 20 μm, only 100 V is required to achieve the highest PR performance. In the wavelength of the 1.55 μm band (~200 nm bandwidth), the conversion length of the PR is only 3.99 μm, the conversion efficiency is close to 100%, and the minimum crosstalk value is −26.2 dB. The presented PR, with its excellent performance, might enable promising applications in the communication system and the photonic integrated circuits.

Polarization rotator with large bandwidth and low insert loss based on lemon core photonic crystal fiber

“…It is observed that the PR reported in Ref. 13 has the shortest device length (only 3.99 μm). Nevertheless, its working bandwidth is limited to only 200 nm.…”

“…9 To date, various PRs have been developed and are mainly classified into two types: on-chip photonic integrated 10,11 and photonic crystal fiber (PCF). 12,13 On-chip PRs are primarily fabricated using platforms such as SOI, Si 3 N 4 , and InP, 11,14,15 which are known for their compactness and suitability for large-scale photonic integration. However, they often necessitate expensive CMOS processes and encounter substantial coupling losses between fibers and chips.…”

“…PRs have been widely employed in polarization multiplexing/demultiplexing systems, 7 coherent light transceivers, 8 and polarization diversity loops 9 . To date, various PRs have been developed and are mainly classified into two types: on-chip photonic integrated 10 , 11 and photonic crystal fiber (PCF) 12 , 13 . On-chip PRs are primarily fabricated using platforms such as SOI, Si3normalN4, and InP, 11 , 14 , 15 which are known for their compactness and suitability for large-scale photonic integration.…”