title: Design of refractive index sensors based on the wavelength-selective resonant coupling phenomenon in dual-core photonic crystal fibers.
abstract: Design strategies for high-sensitivity refractive index sensors based on the principle of wavelength-selective resonant coupling in dual-core photonic crystal fibers are presented. Phase matching at a single wavelength can be achieved between an analyte-filled microstructured core and a small core with a down-doped rod or one small air hole in the center, thus enabling selectively directional resonant-coupling between the two cores. The transmission spectra of the output light presents a notch at the index-matched wavelength, yielding a resonant wavelength depending on the refractive index of the analyte. Numerical simulations demonstrate that both of the two proposed sensors can be used for highly sensitive detection of low-index analyte. In particular, the configuration realized by introducing the fiber with a small air hole in one core can be used to the detection of the analyte index around 1.33 and the sensitivity reach to 1.2×10(4) nm per refractive index unit (RIU). In addition, the detection limit is as low as 2.5×10(-7) RIU at n(a)=1.33.
authors.affiliation: Jiangsu University, School of Mechanical Engineering, Department of Optical Engineering, Zhenjiang 212013, Jiangsu Province, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
authors.forename: Ming-Yang
authors.initials: MY
authors.lastname: Chen
authors.forename: Yong-Kang
authors.initials: YK
authors.lastname: Zhang
authors.forename: Ji-chang
authors.initials: JC
authors.lastname: Yang
mesh_terms: D003198:Computer Simulation; D057230:Limit of Detection; D055616:Microtechnology / Q000295:instrumentation; D055095:Optics and Photonics / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water