Application of Conventional G.652 Optical Fibers with Increased Evanescent-wave Overlap for Detection of Liquids

摘要

The paper discusses conventional telecommunication silica single-mode optical fiber tapers acting as sensors of liquids based on the refractometric principle. Wavelength of 1550 nm is exploited not only due to the facile system integration but especially for the increased evanescent-wave overlap. Based on the simulation results, numerous sensor samples with waist diameters ranging from 4 to 6 µm were prepared in precisely controlled conditions. Proof-of-principle tests were carried out to prove sensitivity enhancement of more than 1400 dB/RIU. Sensitivity enhancement was achieved by a structural modification of the tapered fiber surface. A maximum sensitivity of over 2000 dB/RIU was reached. Our results are essential for reliable, low-cost application of developed sensors, in particular, those used for monitoring of gasoline quality. Furthermore the observed long-term attenuation increase can also be critical for many telecommunication components, especially for those exposed to varying ambient atmosphere.