Open AccessGraphene oxide-film-coated splitting ratio-adjustable Mach-Zehnder interferometer for relative humidity sensing
Author(s) -
Shijie Deng,
Hongyun Meng,
X. Wang,
Xiaofeng Fan,
Q. Wang,
Min-Bo Zhou,
Xin Guo,
Zhongchao Wei,
F. Wang,
Chunhua Tan,
Xu Huang
Publication year - 2019
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.009232
Subject(s) - materials science , optics , relative humidity , cladding (metalworking) , multi mode optical fiber , refractive index , interferometry , graphene , optical fiber , mach–zehnder interferometer , optoelectronics , composite material , nanotechnology , physics , thermodynamics
In this paper, a splitting ratio-adjustable Mach-Zehnder interferometer (MZI) for the measurement of relative humidity (RH) is proposed and experimentally demonstrated. The sensing head contains three sections of single mode fiber (SMF) and two sections of multimode fiber (MMF), in which the two MMFs are spliced among the three SMFs. The MMFs are corroded with hydrofluoric acid and act as mode couplers to split and recombine light owing to the core diameter mismatch with the SMF. A layer of graphene oxide (GO) is coated on the MMFs by dip-coating and natural evaporation. The effective refractive index of the GO will vary when it absorbs the water molecules. As a result, the intensity of the transmission light in the core and cladding of the single mode fiber can be adjusted. Thus, the intensity of the resonant dip will vary when the relative humidity changes. The experimental results show that a humidity sensitivity of 0.263 dB/RH% with a linear correlation coefficient of 99% can be achieved in a relative humidity range of 35% to 85%.