Fiber and Integrated Optics, 29:480–490, 2010 Copyright © Taylor & Francis Group, LLC ISSN: 0146-8030 print/1096-4681 online DOI: 10.1080/01468030.2010.524723 Effect of Residual Resist on Performance of Single-Mode 1  4 Optical Splitter in Photosensitive Polymer RAHUL SINGHAL, 1 M. N. SATYANARAYAN, 2 and SUCHANDAN PAL 3 1 Electrical and Electronics Engineering Group, Birla Institute of Technology and Science, Pilani, India 2 Physics Department, National Institute of Technology Karnataka, Surathkal, India 3 Optoelectronic Devices Group, Central Electronics Engineering Research Institute (Council of Scientific and Industrial Research), Pilani, India Abstract Polymer residues are generally left in the Y-junctions of the conventional splitters. Besides increased insertion loss, the Y-junction residue results in asymmetric distribution of power at device outputs. An analysis of the device performance in the presence of junction residue is presented and a design to overcome the non- uniformities in output power distribution brought about by the presence of the residue is proposed. Keywords optical waveguide, polymeric splitter, Y-branch, Y-junction residue 1. Introduction Polymer waveguides have received increasing attention because of the recent advances in optical polymers and the physical properties that the materials can offer in the context of forming simple inexpensive optical components [1]. Photonic polymer-based devices are particularly attractive because of their ability to be processed rapidly, they are cost effective, and they give high yields. Excellent tailorable optical, mechanical, and physical properties are achievable through using proper polymer and process. Of that matter, polymer material has been accepted as a new-generation material for an optical integrated circuit due to its various advantages as compared to other optical materials. Photosensitive materials are rapidly finding broader applications in micro-scale de- sign. In recent years, a relatively new type of resist, SU-8, has received a lot of attention in the field of micro-fabrication because of its mechanical stability, biocompatibility, and suitability for fabricating high aspect ratio features [2]. Cured SU-8 is highly resistant to solvents, acids, and bases and has excellent thermal stability, making it well suitable for applications in which cured materials are permanent structures of the device. The SU-8 2000 (formulated in cyclopentanone) [3] series of products from MicroChem Corporation, Received 8 April 2010; accepted 14 September 2010. Address correspondence to Mr. Rahul Singhal, Electrical and Electronics Engineering Group, BITS, Pilani Campus, Pilani, 333031, India. E-mail: rahulsinghal@bits-pilani.ac.in 480 Downloaded By: [INFLIBNET India Order] At: 13:34 19 November 2010