Etched multimode microfiber knot-type loop interferometer refractive index sensor

Pal, S.S. and Mondal, S.K. and Tiwari, Umesh and Swamy, P.V.G. and Kumar, Manish and Singh, Nahar and Bajpai, P.P. and Kapur, Pawan (2011) Etched multimode microfiber knot-type loop interferometer refractive index sensor. Review of Scientific Instruments, 82 (9). 095107-095111. ISSN 0034-6748

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We propose a novel refractive index sensor based on multimode microfiber knot-type loop (NL) interferometer. The middle portion (similar to 5 cm) of a 15 cm long multimode fiber is etched in 48% hydrofluoric acid to reduce its diameter to similar to 12 mu m. A NL of diameter < 1 mm is made from the etched fiber. The ends of etched fiber are spliced with single-mode fibers for launching and detecting light from the NL interferometer. The NL introduces path differences to produce interferometric spectra with free spectral range similar to 16 nm. The spectrum shifts as the surrounding refractive index of the loop is changed by adding chemicals. We observe the highest sensitivity of the NL interferometer similar to 172 nm/RIU (refractive index unit) at a refractive index value 1.370 as obtained experimentally using commonly available chemicals. The design could be used as simple, low cost, and highly sensitive biological and chemical sensor

Item Type: Article
Uncontrolled Keywords: fibre optic sensors; light interferometers; refractive index
Subjects: CSIO > Optics
Depositing User: Ms. J Shrivastav
Date Deposited: 22 Apr 2012 22:57
Last Modified: 22 Apr 2012 22:57

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