평판형 광도파로 마하젠더 간섭계에 폴리비닐피롤리돈이 코팅된 습도센서에 관한 연구

Abstract

In this paper, a humidity sensor implemented by Mach-Zehnder interferometer(MZI) in a planar lightwave circuit(PLC) have been demonstrated. Firstly, waveguide channels for MZI was made in a PLC by using photo resist patterning process. One of arms of MZI, which is called by sensing arm, was etched. The length of the etched region is 5 mm, where polyvinylpyrrolidone(PVP) was coated by dip-coating. The PVP interacts to surrounding humidity and results change of refractive index value depending on the degree of relative humidity(RH). As a consequence, variation on effective refractive index of sensing arm in the PVP-coated MZI presented modification of the interferogram in intensity and peak wavelengths depending on the RH around the PLC. The measured results have showed that the proposed humidity sensor works successfully at RH environment ranging 40% to 80%.