Hybrid polymer–glass planar Bragg grating as a temperature and humidity sensor

This paper presents the design and construction of a new planar optical Polymer Waveguide Bragg grating (PWBG) temperature and humidity sensor realized by polymer-glass hybrid technology composition with a new layout concept. The Bragg grating of a sensor was made by a Direct Laser Writing (DLW) in Poly (methyl methacrylate) (PMMA) formed on a multimode waveguide realized in a glass substrate by Ag + ↔ Na + ion exchange. The fabricated hybrid Bragg grating structure exhibited more than 10 dB of the attenuation dip, equivalent to higher than 90% diffraction efficiency. The fabricated hybrid PWBG sensor exhibited high temperature and humidity sensitivity in contrast to glass-based sensors of − 48.6 pm/°C and 54.16 pm·RH −1 , respectively.