Functional Tapered Fiber Devices Using Polymeric Coatings

A wide variety of fiber devices can be created by adding special coatings on tapered sections of optical fibers. In this work we present the fundamentals for the fabrication of tapered optical fibers coated with functional polymers. The required aspects of light propagation in tapered sections of optical fibers are introduced and the relevant parameters enabling light interaction with external media are discussed. A special case of interest is the addition of polymeric coatings with prescribed thicknesses in the tapered sections allowing for adjusting the light propagation features. We assess the use of liquid polymer coatings with varying thicknesses along the taper profile that can be tailored for tuning the transmission features of the devices. Hence, we introduce a methodology for obtaining coatings with predefined geometries whose optical properties will depend on the polymer functionality. As demonstrated with numerical simulations, the use of functional polymer coatings in tapered optical fibers allows for obtaining a wide variety of functionalities. Thus, controlled polymer coating deposition may provide a simple means to fabricate fiber devices with adjustable transmission characteristics.

Review of Microfluidic Approaches for Fabricating Intelligent Fiber Devices: Importance of Shape Characteristics

The shape characteristics, which include the physical dimensions (scale), apparent morphology, surface features, and structure, are essential factors of fibrous materials and determine many of their properties. Microfluidic technologies have...

Helicity Enhanced Torsion Sensor Based on Liquid Filled Twisted Photonic Crystal Fibers

A highly sensitive torsion sensor can be constructed by combining a twisted photonic crystal fiber with a liquid-filled waveguide in its air-hole cladding. The torsion sensitivity of this type of sensor is determined directly by the phase-matching conditions between the fiber core mode and the liquid waveguide mode, which can be improved by tuning the helicity (denoted by the initial twist rate, α0) of the twisted photonic crystal fiber. The enhancement mechanism of α0 on the sensitivity of the proposed torsion sensor is investigated theoretically, followed by experimental verifications, and a torsion sensitivity as high as 446 nm∙mm∙rad−1 can be obtained by tailoring these parameters. Experimental results show that the torsion sensitivity increases with α0 decreasing from 3.142 to 3.925 rad/mm, which are in consistence with that of the numerical predictions. The demonstrated torsion sensor is expected to contribute to the development of highly sensitive torsion-related photonic crystal fiber devices.

In-Fiber Structured Particles and Filament Arrays from the Perspective of Fluid Instabilities

In-fiber structured particles and filament array have been recently emerging, providing unique advantages of feasible fabrication, diverse structures and sophisticated functionalities. This review will focus on the progress of this topic mainly from the perspective of fluid instabilities. By suppressing the capillary instability, the uniform layered structures down to nanometers are attained with the suitable materials selection. On the other hand, by utilizing capillary instability via post-drawing thermal treatment, the unprecedent structured particles can be designed with multimaterials for multifunctional fiber devices. Moreover, an interesting filamentation instability of a stretching viscous sheet has been identified during thermal drawing, resulting in an array of filaments. This review may inspire more future work to produce versatile devices for fiber electronics, either at a single fiber level or in large-scale fabrics and textiles, simply by manipulating and controlling fluid instabilities.

Nanoscale light–matter interactions in metal–organic frameworks cladding optical fibers

The manipulation of light in metal–organic frameworks (MOFs) to investigate the volatile organic compound vapor–MOF interactions by using optical fiber devices is demonstrated.