M.A. van Eijkelenborg

Stable imprinting of long-period gratings in microstructured polymer optical fibre

A simple heat imprinting method for producing stable long-period gratings (LPGs) in microstructured polymer optical fibre (mPOF) is presented as well as the examination of their lifetime and the modelling results of these gratings. Writing LPGs in mPOF presents opportunities for sensors in fibre that can withstand greater bending and strain and are adaptable to specific applications through modification of the cladding structure.

Coupling in a twin-core microstructured polymer optical fiber

Theoretical calculations and experimental results are reported for a microstructured polymer optical fiber twin-core coupler. Beat lengths are calculated using a fully vectorial, Fourier decomposition method, which show that the beat length is extremely sensitive to any core asymmetry. Reasonably good agreement between theory and experiment is obtained.

Microstructured Polymer Optical Fibres: New Opportunities and Challenges

ABSTRACT Microstructured polymer optical fibres [mPOF] were first developed in 2001, and have attracted attention in part because the range of fabrication techniques possible with polymers has allowed novel structures to be made that cannot be made simply in other materials. Their material properties also offer attractive possibilities as polymers can contain a much larger variety of dopants than glass. In this article, we review progress on some of the major challenges of this technology: particularly the need to reduce fibre losses, and report on some recent developments including the fabrication of the first hollow core mPOF. Some initial investigations into changing the material properties are reviewed.

Theoretical, Numerical, and Experimental Analysis of Optical Fiber Tapering

An optical fiber taper is fabricated by heating and stretching a fiber. The resulting taper shape is important as it strongly affects optical performance. In this paper, the tapering process of solid optical fiber is modeled and analyzed under several heating and stretching conditions. The fiber material is assumed to be of non-Newtonian inelastic type. The results show that for a given heating profile, the shape of a tapered fiber is independent of the material properties and the stretching conditions applied at the fiber ends, and a section of uniform waist can be formed as long as the extensional deformation rate in a section of the heating zone is position-independent. Different shapes of fiber tapers can only be achieved by using different heating profiles. Therefore, spatially uniform heating of the fiber within the heating zone is of critical importance for producing a taper with a uniform waist. This is particularly true if the fiber material has a low deformation temperature

Microstructured optical fiber for single-polarization air guidance

An air-core microstructured fiber design that supports a single-polarization, circularly symmetric nondegenerate mode is presented. The fiber design is modeled directly, and the microstructured cladding is analyzed by use of band diagrams to elucidate the mechanism through which polarization nondegeneracy is achieved.

Grating based devices in polymer optical fibre

We describe recent research into devices based on fibre Bragg gratings in polymer optical fibre. Firstly, we report on the inscription of gratings in a variety of microstructured polymer optical fibre: single mode, few moded and multimoded, as well as fibre doped with trans-4-stilbenmethanol. Secondly, we describe research into an electrically tuneable filter using a metallic coating on a polymer fibre Bragg grating. Finally we present initial results from attempts to produce more complex grating structures in polymer fibre: a Fabry-Perot cavity and a phase-shifted grating.

Complex mode coupling within air-silica structured optical fibres and applications

Abstract Novel twin-core coupling at shorter wavelengths (∼633 nm) but not at longer wavelengths (∼1.5 μm) is achieved within an air–silica structured optical fibre. This is the opposite of a conventional twin-core fibre coupler. The implications for a new class of all-optical devices are discussed.

Quantum mechanical diffusion of the polarization of a laser

We have observed the influence of spontaneous emission on the polarization of a miniature HeXe laser (λ = 3.51 μm). The situation where the quantum noise dominates over cavity anisotropies is realized and we demonstrate that this leads to quantum mechanical diffusion of the polarization. Since our laser operates in the bad-cavity regime, the polarization diffusion is slowed down by a memory effect of the gain medium.

Ion dynamics in a novel linear combined trap

We have studied the motional dynamics of ions stored in an ion trap of novel geometry, a linear combined trap, which combines the trapping fields of a linear rf trap and a Penning trap. The motional frequencies of trapped Mg+ ions are measured as a function of the trapping fields, and we find good agreement with theory.

Optimising holey fibre characteristics

We present calculations of the properties of a range of holey fibres with different hole arrangements and symmetries and optimise characteristics such as the splice losses, the dispersion properties and the non-linear effective area.