To come up to the demand for extremely sensitive biosensors for parallel real-time bioanalyses, we present several
configurations of label-free biosensors on Silicon-on-Insulator (SOI) optical chips. We discuss results on microring
resonators with a non-fouling polymer coating, increased sensitivity with slotted wire resonators and the design
and fabrication of an integrated surface plasmon resonance interferometer. The high refractive index contrast
of SOI offers submicron-size features with high quality for dense integration, high sensitivity and detection with
very low analyte volumes. The fabrication method, 193nm deep-UV lithography, allows for mass production of
cheap disposable biochips.
We present several nanophotonic biosensors on silicon-on-insulator: ring resonator based devices, slotted ring
resonators to increase the interaction between light and the sample, and finally devices based on nanoplasmonic
We present simulation and experimental results to achieve increased light extraction of a substrate emitting
OLED. We present a comparison between a grating surface on the OLED and an array of microlenses at the
interface between substrate and air. This experimentally gives -in both cases- a relative improvement of approx.
30 %. We also demonstrate the concept of a RC2LED, applied to an OLED. The RC2LED is composed by
adding a high, low and high index layers between ITO and glass, i.e. the interface between organic layers and
glass. These extra layers create a cavity which numerically gives a relative improvement of over 60% at the
resonance wavelength of the cavity over a wavelength range of 50-100 nm. The influence of an array of micro
lenses in addition to the RC2 layers is also investigated in this paper.
Silicon-on-Insulator (SOI) is a very interesting material system for highly integrated photonic circuits. The high
refractive index contrast allows photonic waveguides and waveguide components with submicron dimensions
to guide, bend and control light on a very small scale so that various functions can be integrated on a chip.
Moreover, SOI offers a flexible platform for integration with surface plasmon based components which in turn
allows for even higher levels of miniaturization. Key property of both waveguide types is the mode distribution
of the guided modes: a high portion of the light is concentrated outside of the core material, thus making them
suitable for sensitive detection of environmental changes.
We illustrate chemical and label-free molecular biosensing with SOI microring resonator components. In
these microring resonator sensors, the shift of the resonance wavelength is measured. A ring of radius 5 micron
is capable of detecting specific biomolecular interaction between the high affinity protein couple avidin/biotin
down to a few ng/ml avidin concentration. We describe the integration of surface plasmon waveguides with SOI
waveguides and discuss the principle of a highly sensitive and compact surface plasmon interferometric sensor
suitable for biosensing. The device is two orders of magnitude smaller than current integrated SPR sensors, and
has a highly customizable behavior. We obtain a theoretical limit of detection of 10-6 RIU for a component of
length 10 microns. We address material issues and transduction principles for these types of sensors.
Besides in chemical sensors, the SOI microring resonators can also be used in physical sensors. We demonstrate
a strain sensor in which the shift of the resonance wavelength is caused by mechanical strain. We have
experimentally characterized the strain sensors by performing a bending test