Effect of stress on silicon oxynitride optical waveguides and devices

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Sun, Yitao
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Integrated demultiplexers and other DWDM components can be fabricated from optical waveguides. In particular, DWDM demultiplexers can be fabricated from silicon oxynitride optical waveguides. Optical attenuation and polarization-dependent propagation are two properties of the optical waveguides that affect the performance of the integrated component. In this thesis, we studied how an externally applied stress can be used to reduce the polarization dependence in silicon oxynitride optical waveguides. We introduce external stress (strain) into optical waveguides of our devices by bending the underlying substrate. Either c mpressive or tensile stress can be introduced in a direction that is either parallel or perpendicular to the direction of optical propagation. An integrated optical demultiplexer is an ideal device for the measurement for birefringence. We used an integrated optical demultiplexer and a tunable laser to measure the stress-induced change of the effective index in our optical waveguides. We have demonstrated that the application of stress can be used to decrease the birefringence by 30% or to increase it by 90%. (Abstract shortened by UMI.)