High-temperature stable and sterilizable waveguide Bragg grating in planar cyclo-olefin copolymer

• Published in: Optics letters Vol. 43; no. 14; p. 3321
• Main Authors: Rosenberger, Manuel, Kefer, Stefan, Girschikofsky, Maiko, Roth, Gian-Luca, Hessler, Steffen, Belle, Stefan, Schmauss, Bernhard, Hellmann, Ralf
• Format: Journal Article
• Language: English
• Published: United States 15.07.2018
• ISSN: 1539-4794
• DOI: 10.1364/OL.43.003321

In this Letter, we demonstrate a high-temperature stable polymer planar waveguide Bragg grating based on cyclo-olefin copolymers. The high glass transition temperature of the polymer material amounting to 178°C, in conjunction with a high-temperature stable UV-curable adhesive used to connect the polymer sensor to a standard single-mode fiber, enables temperature readings of up to 160°C while exhibiting a temperature sensitivity of -7.3  pm/°C. The reflected power of the Bragg wavelength remains constant up to a temperature of 130°C before declining at higher temperatures with an overall reduction of 2.5 dB at 160°C. However, decreasing temperature results in a complete recovery of the peak power, facilitating steam pressure sterilization (129°C, 0.17 MPa) of the polymer planar waveguide Bragg grating.