Reducing the temperature sensitivity of SOI waveguide-based biosensors
2012 (English)In: Silicon Photonics and Photonic Integrated Circuits III / [ed] Vivien, L; Honkanen, SK; Pavesi, L; Pelli, S, SPIE - International Society for Optical Engineering, 2012, Vol. 8431, 84310-84310 p.Conference paper (Refereed)
Label-free photonic biosensors fabricated on silicon-on-insulator (SOI) can provide compact size, high evanescent field strength at the silicon waveguide surface, and volume fabrication potential. However, due to the large thermo optic coefficient of water-based biosamples, the sensors are temperature-sensitive. Consequently, active temperature control is usually used. However, for low cost applications, active temperature control is often not feasible. Here, we use the opposite polarity of the thermo-optic coefficients of silicon and water to demonstrate a photonic slot waveguide with a distribution of power between sample and silicon that aims to give athermal operation in water. Based on simulations, we made three waveguide designs close to the athermal point, and asymmetric integrated Mach- Zehnder interferometers for their characterization. The devices were fabricated on SOI with a 220 nm device layer and 2 ï¿œm buried oxide, by electron beam lithography of hydrogen silsesquioxane (HSQ) resist, and etching in a Cl2/HBr/O2/He plasma. With Cargile 50350 fused silica matching oil as top cladding, the group index of the three guides varies from 1.9 to 2.8 at 1550 nm. The temperature sensitivity of the devices varied from -70 to -160 pm/K under the same conditions. A temperature sensitivity of -2 pm/K is projected with water as top cladding.
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2012. Vol. 8431, 84310-84310 p.
, Proceedings of SPIE, ISSN 0277-786X ; 8431
Slot waveguide, biosensor, athermal, temperature sensitivity
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-95292DOI: 10.1117/12.922263ISI: 000305452700008ScopusID: 2-s2.0-84861987338ISBN: 978-0-8194-9123-7OAI: oai:DiVA.org:kth-95292DiVA: diva2:527513
SPIE Photonics Europe, Brussels, April 16-19, 2012
FunderSwedish Research Council, B0460801
QC 201206132012-06-132012-05-212013-09-16Bibliographically approved