Advanced and Unique Alignment Control Technique for Liquid Crystal-Infiltrated Hollow Core Fiber Devices with High Electrical-Tunability

A flexible and advanced approach is proposed to achieve high-performance, electrically tunable fiber devices using liquid crystals (LCs) within hollow-core fibers (HCFs) with precise alignment. This innovative method integrates a gradient temperature field with the surface polymer-stabilized alignment (SPSA) technique, providing a robust and efficient solution for achieving uniform LC alignment inside HCFs. Experimental results demonstrate that this method offers exceptional control over LC alignment in hollow cylinders, eliminating the need for conventional rubbing processes. The pretilt angle of the LCs can be effectively adjusted by applying a curing voltage, which increases proportionally with the voltage applied. Additionally, the optical properties of the LC-based fiber device can be electrically modulated, with the measured electro-optic effect closely matching theoretical predictions. This proposed alignment control technique offers a groundbreaking and cost-effective solution suitable for mass production and applies to various microstructures, including photonic crystal fibers, micro-waveguides, and silicon photonics, unlocking significant new possibilities for the development of advanced LC-based photonic devices.