Refractive index sensing based on higher-order mode reflection of a microfiber Bragg grating.

A fiber Bragg grating written in a photosensitive microfiber using KrF excimer laser via a uniform phase mask is demonstrated. We have successfully fabricated two Bragg gratings in microfibers having different diameters. In the reflection spectrum of a microfiber Bragg grating (MFBG), we observed two reflection peaks,which agrees with our numerical simulation results. Compared with the fundamental mode reflection, the higher-order reflection mode is more sensitive to the refractive index (RI) variation of the surrounding fluid due to its larger evanescent field. The measured maximum sensitivity is ~102 nm/RIU (RI unit) at an RI value of 1.378 in an MFBG with a diameter of 6 μm.

[1]  Alan D. Kersey,et al.  Analysis of the response of long period fiber gratings to external index of refraction , 1998 .

[2]  Limin Tong,et al.  Single-mode guiding properties of subwavelength-diameter silica and silicon wire waveguides. , 2004, Optics express.

[3]  L. Tong,et al.  Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity , 2009 .

[4]  M. Sumetsky,et al.  Optical microfiber loop resonator , 2005, (CLEO). Conference on Lasers and Electro-Optics, 2005..

[5]  T. Erdogan.  Fiber grating spectra , 1997 .

[6]  M. Sumetsky,et al.  Optical fiber microcoil resonators. , 2004, Optics express.

[7]  Yu Zhang,et al.  All-Optical Format Conversion From RZ to NRZ Utilizing Microfiber Resonator , 2009, IEEE Photonics Technology Letters.

[8]  C. Liao,et al.  Femtosecond laser fabricated fiber Bragg grating in microfiber for refractive index sensing. , 2010, Optics letters.

[9]  F. Kien,et al.  Scattering of an evanescent light field by a single cesium atom near a nanofiber (11 pages) , 2006 .

[10]  Reginald K. Lee,et al.  Highly sensitive fiber Bragg grating refractive index sensors , 2005 .

[11]  Gilberto Brambilla,et al.  Ultra-low-loss optical fiber nanotapers. , 2004, Optics express.

[12]  Limin Tong,et al.  Supported microfiber loops for optical sensing. , 2008, Optics express.

[13]  Yu Wu,et al.  MOEMS Accelerometer Based on Microfiber Knot Resonator , 2009, IEEE Photonics Technology Letters.

[14]  Limin Tong,et al.  All-fiber add-drop filters based on microfiber knot resonators. , 2007, Optics letters.

[15]  D Meschede,et al.  Cold-atom physics using ultrathin optical fibers: light-induced dipole forces and surface interactions. , 2007, Physical review letters.

[16]  A. Cusano,et al.  Thinned fiber Bragg gratings as high sensitivity refractive index sensor , 2004, IEEE Photonics Technology Letters.

[17]  Joel Villatoro,et al.  Fast detection of hydrogen with nano fiber tapers coated with ultra thin palladium layers. , 2005, Optics express.

[18]  Min Zhang,et al.  CO2 laser induced long period gratings in optical microfibers. , 2009, Optics express.

[19]  Gilberto Brambilla,et al.  Embedding optical microfiber coil resonators in Teflon. , 2007, Optics letters.

[20]  S. Campopiano,et al.  Nonuniform thinned fiber Bragg gratings for simultaneous refractive index and temperature measurements , 2005, IEEE Photonics Technology Letters.

[21]  Peter Horak,et al.  Optical microfiber coil resonator refractometric sensor. , 2007, Optics express.

[22]  L. Tong,et al.  Polymer single-nanowire optical sensors. , 2008, Nano letters.

[23]  Limin Tong,et al.  Demonstration of microfiber knot laser , 2006 .

[24]  D. Meschede,et al.  Ultra-sensitive surface absorption spectroscopy using sub-wavelength diameter optical fibers. , 2007, Optics express.

[25]  Wei Jin,et al.  Long-period gratings in wavelength-scale microfibers. , 2010, Optics letters.

[26]  A. Vengsarkar,et al.  Optical fiber long-period grating sensors. , 1996, Optics letters.

[27]  Yu Wu,et al.  Miniature fiber-optic temperature sensors based on silica/polymer microfiber knot resonators. , 2009, Optics express.