Towards hollow-core fiber polarization beam splitting and combining

• Main Author: Raynal, Guillaume Dorian Louis
• Other Authors: Wonkeun Chang
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Electrical and electronic engineering::Optics, optoelectronics, photonics; Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: https://hdl.handle.net/10356/171837
• Institution: Nanyang Technological University

Inhibited Coupling fibers (ICFs) are a new kind of hollow core fibers. During the last decade, researchers have improved the performance of these fibers and low loss over broad transmission windows has now been achieved. This makes ICFs serious candidates for applications in high power and ultrashort beam delivery, motion sensors, and telecommunications. One of the major shortfalls in the wide implementation of ICFs in many of these applications is the general difficulties in integrating the hollow core fiberized devices. Fiber couplers are one of the most crucial components in achieving the system integration, as they are the most fundamental fiber element for beam splitting and combining. Multicore ICFs are highly promising for such applications. This PhD dissertation addresses the influence of the geometry on the coupling properties of a multicore ICF coupler. The coupling properties of an asymmetrical structure and the coupler sensitivity to bending are investigated. Triple core ICF designs that can be easily fabricated are proposed and numerically analyzed. ICF stack-and-draw process is introduced, optimized, and applied to the fabrication of the triple core ICF design. The fibers’ coupling spectral dependence was characterized, and high coupling efficiency is observed for the first time between the three cores. Besides, large polarization extinction ratios could be achieved, enabling the first demonstration of polarization beam splitting in multicore ICF and a significant advancement towards fiber polarization beam combining.