Optical bragg gratings in inorganic-organic hybrid polymers for highly sensitive temperature measurements

We report on the fabrication of an optical sensor based on channel waveguide Bragg gratings in precured inorganic-organic ORMOCER® hybrid-polymer substrates. The particular combination of the optical component and chosen substrate lead to a planar structure with ideal characteristics for highly sensitive temperature measurements. The resulting sensor element shows a linear dependence between temperature and sensor signal with a markedly high sensitivity of up to 294 pm K-1, a thirtyfold higher sensitivity as compared to commonly used silica based fiber Bragg gratings. For the applied interrogation system this sensitivity corresponds to a notable resolution of 20 mK for temperature recordings.