title: Compact microfiber Bragg gratings with high-index contrast.
abstract: We fabricate fiber Bragg grating (FBG) in microfibers (MFs) using focused ion beam milling technique. By periodically etching 100 nm-depth grooves on the surface of silica MFs with diameters less than 2 μm, evident grating features with transmission dip up to 15 dB are obtained. Because of the high-index contrast of the gratings structure, the length of the microfiber Bragg grating (MFBG) can be reduced to 500 μm level. Using a 518 μm-length 1.8 μm-diameter MFBG, we also demonstrate sensitivity up to 660 nm per refractive index unit (RIU) for refractive index (RI) sensing. The highly compact MFBGs demonstrated here may serve as low-dimensional building blocks for miniaturized photonic components and devices.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Liu
authors.forename: Chao
authors.initials: C
authors.lastname: Meng
authors.forename: A Ping
authors.initials: AP
authors.lastname: Zhang
authors.forename: Yao
authors.initials: Y
authors.lastname: Xiao
authors.forename: Huakang
authors.initials: H
authors.lastname: Yu
authors.forename: Limin
authors.initials: L
authors.lastname: Tong