In this work we show results of controlled tapered fibers using a Vytran instrument. The tapered silica fibers were produced by pulling a 50μm length by heating time. The minimum taper diameter was around 3μm and the maximum taper length was around 600μm. The evanescent field effect, in the near infra red (NIR) region, was observed to the tapers with diameter inferior to 15μm. These micro-size tapers no modify the waveguide dispersion spectra. This device could be used to splice a conventional fiber to photonic crystal fibers and also as liquid and gas sensors In this work is reported a fiber optic sensor in the form of taper using the concept of the evanescent field. We show the sensor sensitivity using different liquid materials. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).8120 The Society of Photo-Optical Instrumentation Engineers (SPIE)Foster, M.A., Gaeta, A.L., Ultra-low threshold supercontinuum generation in sub-wavelength waveguides (2004) Opt. Express, 12 (14), pp. 3137-3143Jung, Y., Brambilla, G., Richardson, D.J., Broadband single-mode operation of standard optical fibers by using a sub-wavelength optical wire filter (2008) Opt. Express, 16 (19), pp. 14661-14667Tong, L., Gattass, R.R., Ashcom, J.B., He, S., Lou, J., Shen, M., Maxwell, I., Mazur, E., Subwavelength-diamter silica wires for low-loss optical wave guiding (2003) Nature, 426, pp. 816-819Zhang, L., Gu, F., Lou, J., Yin, X., Tong, L., Fast detection of humidity with a subwavelengthdiameter fiber taper coated with gelatin film (2008) Opt. Express, 16 (17), pp. 13349-13353Espinola, R.L., Dadap, J.I., Osgood Jr., R.M., McNab, S.J., Vlasov, Y.A., C-band wavelength conversion in silicon photonic wire waveguides (2005) Opt. Express, 13 (11), pp. 4341-4349Lizé, Y.K., Mägi, E.C., Ta'Eed, V.G., Bolger, J.A., Steinvurzel, P., Eggleton, B.J., Microstructured optical fiber photonic wires with subwavelength core diameter (2004) Opt. Express, 12 (14), pp. 3209-3217Foster, M.A., Turner, A.C., Lipson, M., Gaeta, A.L., Nonlinear optics in photonic nanowires (2008) Opt. Express, 16 (2), pp. 1300-1320Siviloglou, G.A., Suntsov, S., El-Ganainy, R., Iwanow, R., Stegeman, G.I., Christodoulides, D.N., Enchanced thirdorder nonlinear effects in optical AlGaAs nanowires (2006) Opt. Express, 14 (20), pp. 9377-9384www.orc.soton.ac.uk/ofnrd.html, Optical Fibre Nanowires and Related Devices Group, University of SouthamptonCordeiro, C.M.B., Wadsworth, W.J., Birks, T.A., Russell, P.St.J., Engineering the dispersion of tapered fibers for supercontinuum generation with a 1064 nm pump laser (2005) Opt. Lett., 30 (15), pp. 1980-1982Wadsworth, W.J., Ortigosa-Blanch, A., Knight, J.C., Birks, T.A., Man, T.-P.M., Russell, P.St.J., Supercontinuum generation in photonic crystal fibers and optical fiber tapers: A novel light source (2002) J. Opt. Soc. Am. B, 19 (9), pp. 2148-2155Shi, L., Chen, X., Liu, H., Chen, Y., Ye, Z., Liao, W., Xia, Y., Fabrication of submicron-diameter silica fibers using electric strip heater (2006) Opt. Express, 14 (12), pp. 5055-5060Sagué, G., Baade, A., Rauschenbeutel, A., Blue-detuned evanescent field surface traps for neutral atoms based on mode interference in ultra-thin optical fibres (2008) New J. Phys., 10, pp. 113008+18Nayak, K.P., Melentiev, P.N., Morinaga, M., Le Kien, F., Balykin, V.I., Hakuta, K., Optical nanofiber as an efficient tool for manipulating and probing atomic fluorescence (2007) Opt. Express, 15 (9), pp. 5431-5438Xu, F., Horak, P., Brambilla, G., Optical microfiber coil resonator refractometric sensor (2007) Opt. Express, 15 (12), pp. 7888-7893Leon-Saval, S.G., Birks, T.A., Wadsworth, W.J., Russell, P.S.J., Supercontinuum generation in submicron fibre waveguides (2004) Opt. Express, 12 (13), pp. 2864-2869Tran, T.X., Biancalana, F., An accurate envelope equation for light propagation in photonic nanowires: New nonlinear effects (2009) Opt. Express, 17 (20), pp. 17934-17949Biancalana, F., Tran, Tr.X., Stark, S., Schmidt, M.A., Russell, P.S., Emergence of geometrical optical nonlinearities in photonic crystal fiber nanowires (2010) Physical Review Letters, 105, p. 093904