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Title Inline microring reflector for photonic applications
Publication Date
Date Accessioned
Degree PhD
Discipline/Department 1200
Degree Level doctoral
University/Publisher University of Illinois – Urbana-Champaign
Abstract The microring is a compact resonator that is used as a versatile building block in photonic circuits ranging from filters, modulators, logic gates, sensors, switches, multiplexers, and laser cavities. The Bragg grating is a periodic structure that allows the selection of a narrow bandwidth of spectrum for stable lasing operation. In this dissertation, we study analysis and simulations of a compact microring based reflector assembled by forming a Bragg grating into a loop. With the appropriate design, the microring resonance can precisely align with the reflection peak of the grating while all other peaks are suppressed by reflection nulls of the grating. The field buildup at the resonance effectively amplifies small reflection of the grating, thereby producing significant overall reflection from the ring, and it is possible to achieve a stable narrow linewidth compact laser by forming a single mode laser cavity. The device operation principle is studied from two distinct perspectives; the first looks at coupling of two contra-directional traveling waves within the ring whereas the second aspect investigates relative excitation of the two competing microring resonant modes. In the former method, we relate the steady state amplitudes of the two traveling waves to the reflection spectrum of the grating and solve for the reflection and transmission response for each wavelength of interest. In the latter approach, we expand the field in terms of the resonant modes of the ring cavity and derive transfer functions for reflection and transmission from the nearby mode frequencies. The angular periodicity of the reflective microring geometry allows us to effectively simulate the resonant modes from a computational domain of a single period grating when the continuity boundary condition is applied. We successfully predict the reflection and transmission response of a Si3N4/SiO2 microring reflector using this method – otherwise too large to carry out full-wave simulation – and show that the prediction agrees very well with the measurement result.
Subjects/Keywords photonic; optics; microring; reflector; Bragg; grating; cavity; resonator
Contributors Goddard, Lynford L. (advisor); Goddard, Lynford L. (Committee Chair); Liu, Gang Logan (committee member); Bernhard, Jennifer T. (committee member); Jin, Jianming (committee member)
Language en
Rights Copyright 2013 Young Mo Kang
Country of Publication us
Record ID handle:2142/44375
Repository uiuc
Date Indexed 2018-11-19
Grantor University of Illinois at Urbana-Champaign
Issued Date 2013-05-24 22:09:25

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