3D printed micro-nano waveguide ultrashort Bragg grating on optical fiber tip as a contact liquid reagent temperature sensor

An optical fiber ultrashort polymer micro-nano

waveguide Bragg grating (PMWG) for contact liquid

temperature sensor was fabricated on the single-mode fiber tip

by the femtosecond laser induced two-photon polymerization.

This structure is composed of a conical waveguide, a micro-nano

waveguide Bragg gating and a pair of tripods. The overall length

of the structure is about 160 μm and the cross-sectional

dimension of micro-nano waveguide is only 1.6*1.5 μm. The

length of polymer micro-nano waveguide Bragg grating is less

than 125 μm, which is about one fiftieth of the traditional FBG.

The micro-nano waveguide grating was placed in deionized

water. The surrounding liquid acts as the cladding of the

micro-nano waveguide grating. The direct contact of the grating

structure with the external liquid will result in faster and more

sensitive liquid temperature response. In the liquid temperature

corresponding experiment, the sensitivity of the micro-nano

waveguide grating is up to 0.3385 nm/℃ with deionized water

temperature changing from 27.7 ℃ to 49.2 ℃. It has a good

application prospect in the field of optical fiber biochemical

micro-nano detection, microfluidics, etc.