During the last decade, polymer-based integrated optics has shown promising development for mass production. An optical waveguide sensor with a low refractive index difference between the core and the surrounding medium could enable the manufacture of low-cost biosensors from materials with modifiable refractive indices. This type of Young interferometer sensor was fabricated from siloxane. The empirical sensitivity of the sensor was studied and found to be 5x10-6 refractive index units (RIU).
Uusitalo, S., Känsäkoski, M., Kärkkäinen, A., Hannu-Kuure, M., Aikio, S., & Kopola, H. (2010). Biosensing with low-index waveguides: An experimental study of a polymer-based young interferometer sensor. Micro and Nanosystems, 2(2), 65-69. https://doi.org/10.2174/1876402911002020065