Year: 2008
Type: dissertation
Abstract: This work describes the development of a telecommunications switch, sensor platforms for high resolution measurement of refractive index, and a fluorescencebased biosensor.All of these devices are based on optical waveguides fabricated from UV photocurable hybrid sol-gel materials.To address each application, the optical waveguides have been fabricated in a planar geometry referred to as planar lightwave circuits (PLCs).PLCs permit the manipulation of light on the micro-scale permiting development of miniature and compact devices.A ground-up approach to development has been adopted starting with modelling and design of each platform, material development, and leading on to fabrication and characterisation of the optical devices.Modelling has been carried out using beam propagation method software.In parallel with platform development, sol-gel material optimisation work has included the identification of photoreactive instabilities in the initial sol-gel material and the successful adaptation of the formulation.Fabrication involved use of a UV mask alignment instrument, and development of a direct laser writing system.In the area of telecommunications, an optical switch aimed at protection and restoration in networks has been successfully developed.It employs a Mach-Zehnder interferometer configuration which exploits the high thermo-optic effect of the sol-gel material in order to switch the input light signal between the output ports.In parallel with the Mach-Zehnder design a novel design based on multimode interference couplers was also successfully implemented.The refractive index sensing platforms are suitable for the detection of any chemical/biochemical change that results in an accompanying refractive index change.As a proof of principle, the basic platform was adapted as a humidity sensor by the deposition of a humidity-sensitive porous sol-gel layer.For a fluorescence-based biosensor platform, the evanescent field of the waveguide is used to excite fluorescence from a multitude of different surface bound biomolecules, allowing their detection and quantification.As verification, a mouse IgG immunoassay was successfully carried out on the platform.This is a generic multianalyte platform which can be applied to the detection of any analyte in areas as diverse as biomedical diagnostics, biowarfare detection, food safety, and narcotics detection to name a few.viii cost mass-production of PLCs for a variety of applications.Here, the intrinsic advantages of PLC platforms have been exploited for the fabrication of novel telecommunications switches based on the thermo-optic effect.A number of novel PLC sensing platforms have also been developed, focused on refractometric-and fluorescence-based detection formats.
Author: Robert Copperwhite
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W154938873