Temperature sensor based on surface Bragg grating of sidepolished fiber

To fabricate the Bragg grating on the sidepolished fiber(SPF) and improve the flexibility of grating design, a novel method for fabricating surface Bragg grating on SPF with dichromate gelatin(DCG) was demonstrated. SPF was fabricated by wheel polishing method and DCG was spin coated on the polished surface of SPF as photoresist. Using holography technique, Bragg grating was fabricated on the polished surface. Spectral measurement results show that a significant reflection peak can be observed at 1 480.2 nm, which is well corresponding to the transmission valley. The modulation amplitude of this reflection peak is up to 15.9 dB, due to the reflection of surface Bragg grating. Temperature sensing experiment results show that with temperature increasing, the reflection peak can have red shift. its sensitivity is 17.84 pm/℃. This fiber sensor has good potential in the application of fiber sensor and fiber filter.