Quantitative Determination of Photosensitivity Proximity Effects in Multi Exposure Direct UV Writing for High Density Integrated Optics

Price competition and the need for miniaturisation provide powerful incentives for engineers to seek higher device densities in integrated optics. One of the more recently developed techniques known to be capable of fabricating high density integrated optical devices is direct UV writing. This technique has in the past demonstrated successful fabrication of directional power splitters, Bragg gratings and small angle X-couplers. A major advantage of direct UV writing over conventional photolithography and etching techniques is the ability to tailor the refractive index of a given wave guiding structure by exposing the same region with UV light repeatedly, thus improving the overall device performance. We discussed how proximity effect can be applied to the design of optimised UV written architectures for high density integrated optics. Particular examples will include asymmetric X-couplers and multi-mode planar Bragg gratings for use in sensing and telecommunication applications.