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UBC Theses and Dissertations

Silicon photonic modulators and filters for optical interconnects Caverley, Michael


The goal of this work is to enhance the performance of and demonstrate new applications for silicon photonic modulators and filters. We demonstrate a variety of novel designs and applications of silicon photonic devices for integrated optical interconnects. First, we demonstrate a biasing scheme for travelling-wave Mach-Zehnder modulators in which the bias voltage is applied separately from the data signal. Using this biasing scheme, there is no low frequency cutoff and there is no power consumption in the termination resistor from the bias voltage, which results in an improved modulator having a lower overall power consumption. We experimentally show, as a proof-of-concept, successful high-speed modulation, at a data rate of 28 Gb/s, of a modulator which uses this biasing scheme. Next, we present a novel modulator design in which a microring modulator is placed into each arm of a Mach-Zehnder interferometer. This design uses the sharp phase response of a microring resonator near its resonance so that the light experiences a large phase change when a voltage is applied to the p-n junction phase shifters within the microring. We use temporal coupled mode theory to simulate the time-domain response of this modulator. We then demonstrate a novel modulator design which uses a quarter-wave phase-shifted Bragg grating. The modulator, which was fabricated using 193 nm optical lithography, has open eye diagrams at a data rate of 32 Gb/s. We also show that using a 2³¹-1 pseudorandom binary sequence pattern, the modulator has a bit error rate (BER) less than 10⁻¹² at a data rate of 20 Gb/s and has a BER less than 10⁻¹⁰ at a data rate of 25 Gb/s. Finally, we demonstrate a contra-directional grating coupler-based filter on silicon in an optical add-drop multiplexer configuration and show that it can successfully add and drop a 12.5 Gb/s signal at the same wavelength without substantial signal degradation.

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Attribution-NonCommercial-NoDerivs 2.5 Canada