Optical fiber flowmeter based on graphene oxide coated michelson interferometer

Measuring gas and liquid flow rate is paramount in various scientific and industrial applications. This work presents an optical fiber flowmeter based on a graphene oxide (GO) coated Michelson interferometer. The interferometer is fabricated using a long-period fiber grating (LPFG) followed by a GO-coated single-mode fiber (SMF). By radiating the GO coating, it experiences photothermic effect that induces local heating of the film. This results in a variation in the effective refractive index in the cladding modes, which induces a phase shift on the interferometer spectrum. When a gas flow is introduced near the coated fiber, the “hot-wire” region will experience a reduction in temperature proportional to the flow rate. The flowmeter exhibited a linear wavelength shift to the flow rate with an absolute sensitivity of 17.4 ± 0.8 pm/(L.min-1) for gas flow rates between 2 and 8 L/min. Furthermore, the dynamic response of the sensor was studied, attaining a maximum response time of 1.1 ± 0.4 s