John E. Cunningham

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We present thermally tunable silicon racetrack resonators with an ultralow tuning power of 2.4 mW per free spectral range. The use of free-standing silicon racetrack resonators with undercut structures significantly enhances the tuning efficiency, with one order of magnitude improvement of that for previously demonstrated thermo-optic devices without(More)
We report the first sub-picojoule per bit (400fJ/bit) operation of a silicon modulator intimately integrated with a driver circuit and embedded in a clocked digital transmitter. We show a wall-plug power efficiency below 400microW/Gbps for a 130nm SOI CMOS carrier-depletion ring modulator flip-chip integrated to a 90nm bulk Si CMOS driver circuit. We also(More)
We report a high-speed ring modulator that fits many of the ideal qualities for optical interconnect in future exascale supercomputers. The device was fabricated in a 130 nm SOI CMOS process, with 7.5 μm ring radius. Its high-speed section, employing PN junction that works at carrier-depletion mode, enables 25 Gb/s modulation and an extinction ratio >5 dB(More)
Using low parasitic microsolder bumping, we hybrid integrated efficient photonic devices from different platforms with advanced 40 nm CMOS VLSI circuits to build ultra-low power silicon photonic transmitters and receivers for potential applications in high performance inter/intra-chip interconnects. We used a depletion racetrack ring modulator with improved(More)
We report ultra-low-power (690fJ/bit) operation of an optical receiver consisting of a germanium-silicon waveguide detector intimately integrated with a receiver circuit and embedded in a clocked digital receiver. We show a wall-plug power efficiency of 690microW/Gbps for the photonic receiver made of a 130nm SOI CMOS Ge waveguide detector integrated to a(More)
We present two effective approaches to improve the responsivity of high speed waveguide-based Ge photodetectors integrated on a 0.25 μm silicon-on-insulator (SOI) platform. The main cause of poor responsivity is identified as metal absorption from the top contact to Ge. By optimizing Ge thickness and offsetting the contact window, we have demonstrated that(More)
Optical proximity communication (OPxC) with reflecting mirrors is presented. Direct optical links are demonstrated for silicon chips with better than -2.5dB coupling loss, excluding surface losses. OPxC is a true broadband solution with little impairment to the signal integrity for high-speed optical transmission. With wavelength division multiplexing (WDM)(More)
We report a vertical p-i-n thin-film germanium photodetector integrated on 3microm thick large core silicon-on-insulator (SOI) waveguides. The device demonstrates very high external responsivity due to the low fiber coupling loss to the large core waveguides. The germanium width and thickness are carefully designed to achieve high responsivity yet retain(More)