Edwin Jan Klein - Universiteit Twente

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Abstract
This thesis describes the design, realization and characterization of densely integrated
optical components based on thermally tunable microring resonators fabricated in
Si3N4/SiO2.
Chapter 1 “Introduction”
In this chapter a brief introduction and overview are given of current broadband
communication networks to provide a background for the work presented in this
thesis. Current copper based networks are unable to meet future bandwidth demands
and will therefore be slowly replaced with optical networks. A promising technology
for these networks is WDM-PON. Currently, however, this technology is too
expensive. The Broadband Photonics and NAIS projects within which the presented
work was carried out both seek to lower the cost of WDM-PON implementations
through dense integration of reconfigurable optical components based on optical
microring resonators.
Chapter 2 “The micro-resonator”
In the second chapter the operating principle of a microring resonator is explained and
the basic parameters that govern its operation are introduced. The filter frequencydomain
responses for single as well as serial higher order systems based on two
resonators are derived. Solutions for typical problems that occur when designing
resonators such as a Free Spectral Range (FSR) that is too small or a filter shape that
does not meet the desired specifications are also given.
Chapter 3 “Design”
In the third chapter the design of microring resonator based devices is discussed in
general terms. Several performance parameters are introduced that can be used to
translate the requirements of a certain application into specific values of the basic
microring resonator parameters.
For microring resonators with a radius of 50 µm (FSR≈4.2 nm) , which is the case for
most of the devices presented in this thesis, it is shown that for telecom applications a
good target for the field coupling coefficients is between 0.4 and 0.6 when reasonable
losses of 2 dB/cm are assumed for the resonator. The methodologies for creating an
actual resonator design from these basic parameters are also given. In addition design
aspects on a device level (the whole device layout) are discussed. Here it is shown
that for these resonators the miniaturization of devices that incorporate these