Development and applications of UV written waveguides
This thesis presents a description of the development of structures suitable for the technique of Direct UV Writing and demonstrates applications for which the resultant waveguiding devices may be used. The later stages of the thesis present several applications of the direct UV writing process and of devices fabricated by the technique. Firstly, direct grating writing is used as a waveguide analysis technique to measure the effects of thermal annealing on UV written structures in PECVD and FHD fabricated samples. Following this, the use of UV written devices as refractive index sensors is shown using the detection of phase transitions in water and a liquid crystal as examples. The detection of supercooling in water is demonstrated and identification of the supercool state is found to be straightforward. Building on these results, the first tunable planar Bragg grating using a liquid crystal layer is fabricated and experimentally demonstrated. An electrically controlled tuning range of 35GHz is recorded.