We describe the development of optical waveguides and adiabatic tapers based on SiON-glasses for a lab-on-chip device
with fluorescence optical detection. Sensing is based on evanescent near-field excitation of biomolecules captured on the
surface of a thin waveguide. First, the composition of SiON waveguides was optimized to reduce losses for visible light.
Waveguides with refractive index of ~1.63 showed propagation losses of ~0.8-0.9 dB/cm at 633 nm. A low loss adiabatic
taper was developed to convert efficiently the light from a multi mode waveguide into a thin mono-modal one. Design of
the taper was done by calculating numerically the transmission efficiency using a finite-difference time-domain method
(FDTD). Simulation results show that losses lower than ~1 dB are obtained for taper lengths of 100 to 300 micron, which
indicates an efficient mode conversion. Based on this, tapers of different lengths were realized by grayscale lithography
and by reactive ion etching. Their optical testing shows best insertion losses of ~1 dB at 633 nm for multimode to
monomode waveguide transitions.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.