Abstract
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 [1]. 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 as reported in [2]. However, little is known about the photosensitivity behaviour of regions within the immediate vicinity of an earlier UV exposed area, also known as the proximity effect. This effect is critical when fabricating high density devices via direct UV writing due to the reduced spacing between two independent structures. Here we present an approach for quantitative characterisation of this effect. Determination of photosensitivity levels at a fixed spacing from an initially exposed region is obtained by defining a set of Bragg gratings with different Bragg wavelengths, and subsequently using the effective index information to deduce the UV induced index increase.
© 2007 IEEE
PDF ArticleMore Like This
I. J. G. Sparrow, G. D. Emmerson, C. B. E. Gawith, S. P. Watts, V. Albanis, R. B. Williams, and P. G. R. Smith
CTuU3 Conference on Lasers and Electro-Optics (CLEO:S&I) 2004
G. D. Emmerson, C. B. E. Gawith, S. P. Watts, I. J. G. Sparrow, V. Albanis, R. B. Williams, P. G. R. Smith, S. G. McMeekin, J. R. Bonar, and R. I. Laming
MD36 Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (BGPP) 2003
K. Færch and M. Svalgaard
BFD1 Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (BGPP) 2001