Design and Application of Anti-Symmetric Grating for Optical Communication Systems

Abstract

In this dissertation, theoretical and experimental investigations leading to the development of a novel type of Bragg grating, denominated Anti-symmetric Waveguide Bragg Grating (AWBG), are presented. This type of Bragg grating can be applied in diverse areas of optical communication and optical processing by providing compact, integratable devices which do not need circulators to separate incoming from outgoing signals. The principle of the AWBG is derived from Coupled-Mode Theory, and for the experimental demonstration, designs were fabricated using silica-on-silicon technology. The advantages of the AWBG are compared with the previously studied Tilted Bragg grating. The anti-symmetric grating exclusively produces a reflection with mode conversion in a two-mode waveguide. This improves the performance by minimizing noise and crosstalk produced by reflection without mode conversion. In addition, the operational bandwidth and versatility are enhanced while keeping the compactness and simplicity of the devices.In this work, the AWBG concept is experimentally demonstrated using several devices: an optical add/drop multiplexer based on AWBG, sampled Bragg gratings, a novel type of interleaved sampled Bragg gratings, and spectral amplitude encoders/decoders. In addition, theoretical work on several applications of the AWBG in spectral phase encoding/decoding and optical cryptography are presented.