Date of Completion

9-26-2017

Embargo Period

9-26-2017

Keywords

optoelectronics, microring resonators, photodetectors

Major Advisor

Geoff Taylor

Associate Advisor

Rajeev Bansal

Associate Advisor

John Ayers

Field of Study

Electrical Engineering

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Internet traffic is increasing exponentially with the continued growth of online streaming, cloud computing, and social media services. This increases demand on data centers that must handle the transmission, routing, and storage of the data. As bandwidth is scaled up, more power efficient systems are required to reduce cost and power consumption, while maintaining thermal requirements. Gigabit connections between the labyrinth of network servers are traditionally made of copper, but link distances are typically limited to ten meters, and the required electronic equalizations add to the power budget. To achieve high bitrates with low energy per bit, optical interconnects are displacing copper, at increasingly short distances. This trend will continue as optical transceiver costs fall and the devices within become more energy efficient.

A category of optoelectronic devices that apply resonant-cavities are uniquely suited to address optical interconnect improvements. The resonant-cavity enhances the device function, by increasing its sensitivity. In this dissertation two such devices are investigated for application in high speed, energy efficient, short reach optical interconnects for data centers.

The first is the microring resonator, which is a planar photonic circuit capable of multiple functions such as optical switching and intensity modulation. An optical switching fabric based on microrings is designed and optical data transmission is simulated. Operated as a modulator, the microring is analyzed theoretically to develop a novel small-signal model that agrees with experimental results, and accurately predicts dynamic power dissipation.

The second device is a novel GaAs-based thyristor photodetector. Operated with surface illumination, the epitaxial structure of the device is compatible with VCSEL integration. The for the fabricated device are presented with an analysis of internal current gain, inherent to the thyristor operation. Experimental findings are applied to the development of an equivalent circuit model, in order to derive the rise time of the detector. The thyristor detector shows promising results in that high sensitivity is achieved along with a predicted rise time less than 25 ps.

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