UV written waveguide devices - Bragg gratings and Applications in Sensors

Ultra-violet laser direct writing provides a powerful way of creating integrated optical devices. The work reported here describes developments in this field, and particularly the use of two-beam writing to create Bragg gratings in planar integrated format. The work shows how these structures can be used in a wide range of applications, ranging from creation of wide-band couplers, through to extremely sensitive sensor devices. UV direct writing removes many of the constraints normally associated with planar integrated optics. It is a mask-free process that uses direct computer control and it dispenses with the etching steps normally required to make low-loss waveguide devices. The work reported will show how this flexibility of format may be combined with novel substrate structures to allow new device types.