In-line microfluidic sensor based on dual S-taper fiber interferometer for measurement of glucose concentration

S-Taper Fiber Based Moisture Sensing in Power Transformer Oil

“…The cladding modes are sensitive to the change in SRI, unlike the core mode [21]. Furthermore, eff n  is positive with the SRI increasing due to higher-order cladding modes, excited by the bending structure [22,28]. For the S-taper fiber applied to the detection of moisture content in transformer oil, the RI of the moisture-in-oil sample increases with the moisture content decreasing, leading to the increment of eff n  .…”

“…S-taper fiber is a kind of microstructure fiber with "S" shape, which can be made by single-mode fiber (SMF), with the advantages of high repeatability, simple fabrication, compact size and high sensitivity. Due to its bending structure, the S-taper fiber produces inter-mode interference and is highly sensitive to refractive index (RI), so it is commonly applied to refractive index sensors [22].…”

“…Numerous methods for the detection of moisture content in transformer oil have been reported, which can be classified into chemical [8,9], electrical [10][11][12], acoustic [13] and optical [14][15][16][17][18][19][20][21][22][23][24][25][26] techniques according to the corresponding working principles. Chemical chromatography and Karl-Fischer titration [8,9] are the most common moisture-in-oil detection methods in laboratory by virtue of their low detection limits and high precision.…”

“…In contrast, the S-taper fiber sensor is put forward owing to the advantages of high sensitivity, high repeatability, simple fabrication, compact structure and resistance to surrounding temperature change. At first, the S-taper fiber was used to detect surrounding refractive index (SRI), which determines the wavelength of the transmission dip of its transmission spectrum [21,22]. The refractive index induced wavelength shift has been validated to trace the physical quantity to be measured [23].…”