Photonic liquid crystal fiber (PLCF) sensing

• Main Author: Chan, Yen Mei.
• Other Authors: Chan Chi Chiu
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Chemical engineering::Biotechnology
• Online Access: http://hdl.handle.net/10356/39707
• Institution: Nanyang Technological University

Photonic Crystal Fibers (PCFs) are characterized by the pattern arrangement of micrometer-size air-holes along the length of the fiber. This micro-structured waveguide is capable of guiding light by a modified form of total internal reflection (TIR) and by photonic bandgap (PBG) effect. The existence of the air-holes in the cladding region has opened up opportunities to introduce new materials into the fiber. Thus, this allows interactions between light and the hole-material, whilst maintaining the microstructure of the fiber. In this paper, we have infiltrated a solid-core PCF with E7 nematic liquid crystals to develop a Photonic Liquid Crystal Fiber (PLCF). With liquid crystals in the microholes, the fiber functionality and sensing can be increased as it operates on the PBG effect, instead of the conventional TIR mechanism. The first part of this research focuses on the infiltration of liquid crystals into the PCF to form the PLCF. Thereafter, it looks into the fusion-splicing process necessary to connect the PLCF with a single-mode fiber (SMF; patch-cord) so that experiments can be conducted more effectively. This forms the basic set-up to investigate the effect of mechanically induced long period gratings (LPGs), temperature changes and external electric field on the PLCF. As far as possible, experimental results in these areas are discussed succinctly, and deductions are verified using control set-ups involving an empty solid-core PCF. Lastly, an extended investigation is also included to analyze mechanically induced tilted LPGs on the PLCF, empty PCF and solid-core PCFs infiltrated with lower refractive index oils.