Abstract

Manipulation and precise control of propagation and modal characteristics is crucial for designing and performance optimization of several fiber-optic devices [1]. This necessitates to the origin and advent many specialty optical fibers namely, photonic crystal fiber (PCF), photonic bandgap fibers, hybrid fiber etc. owing to the design flexibility offered in such waveguide structures. In addition to this, responsive liquid infiltration (thermo-optic, nematic) of micro-holes/air-holes of PCF also emerged as a promising technique for obtaining tunable fiber devices. However, limitations exist in the dynamic range of tunability, difficulty in selective infiltration through capillary action, high absorption losses of liquid around operating wavelength. Thinking in this line, in this work, a novel approach of obtaining a dynamic few-layer fiber (FLF) is proposed such that the outer cladding (third layer) composed of a hygroscopic material (e.g. gelatin) can be designed to control the propagation of core and leaky cladding modes to a large extent through the ambient relative humidity (RH) [2]

© 2016 Japan Society of Applied Physics, Optical Society of America