Inline microring reflector for photonic applications

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2013

Author dc:creator

• Kang, Young Mo

Contributors dc:contributor

• Goddard, Lynford L.
• Liu, Gang Logan
• Bernhard, Jennifer T.
• Jin, Jianming

• photonic
• optics
• microring
• reflector
• Bragg
• grating
• cavity
• resonator

Statement dc:rights

• Copyright 2013 Young Mo Kang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/44375

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/44375