Femtosecond laser microprinting of a polymer fiber Bragg grating for high-sensitivity temperature measurements

We demonstrate the microprinting of a novel suspended polymer fiber Bragg grating for high-sensitivity temperature measurements. The proposed sensor was developed using a femtosecond laser-induced multiphoton polymerization technique. The grating was cured in a single-groove silica tube spliced between two single-mode fibers. Its transmission spectrum, mode field, and temperature response were thoroughly investigated. A sensitivity of -220 pm/°C was achieved over a temperature range of 24°C to 40°C, which is meaningful in biosensing applications. This all-in-fiber polymer Bragg grating exhibits high temperature sensitivity, excellent mechanical strength, and ultrahigh integration. As such, a temperature sensing element of this type would be a beneficial tool for biological measurements.