Selective infiltration of dual-core photonic crystal fiber

Abstract

Selective infiltration of air-holes in photonic crystal fibers (PCFs) with functional materials can be used to develop optical fiber devices with many advanced functions, such as asymmetric coupling, tunable beam diffraction, birefringence, high nonlinearity and short coupling length. There are four common techniques used to achieve selective infiltration: manual gluing, injection-cleaving, air-holes collapsing, and focused ion beam (FIB) micromachining. However, these methods can be practically tedious to implement or have limitations on applicable PCF structures. In this project, a new methodology has been proposed and demonstrated to enable the precise selective infiltration of PCF by the use of femtosecond laser-assisted micromachining. Through the proposed method, we have successfully achieved the selective infiltration of single air-hole with diameter of 2.5µm and pitch size of 3.75µm within a dual-core PCF (DC-PCF). The proposed method is practically straightforward, precise, and highly repeatable to enable fabrication of advanced PCF-based fiber devices.