High-sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber

Abstract

A novel, high sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber (ECF) has been designed and implemented in this paper. The exposed core fiber has noncircular symmetry and thus exhibits birefringence and can form a sensing element within a Sagnac loop interferometer. The exposed-core fiber design provides direct access to the evanescent field, allowing the measurement of bulk refractive index (RI) with a sensitivity of up to-3,137 nm/RIU while maintaining the fiber's robustness. The sensor can also detect the localized refractive index changes at the fiber core's surface as the result of a biological binding event. We demonstrate the use of this sensor for label-free sensing of biological molecules by immobilizing biotin onto the fiber core as the probe to capture the target molecule streptavidin.

Quantum noise limited nanoparticle detection with exposed-core fiber

“…The region where the evanescent field propagates determines the interaction volume between the light and the surrounding medium. This accessible interaction volume allowed a wide variety of applications including sensors for biology [18,19]. For example, exposed-core fibers have been used for the detection of fluorescence signals [20,21] and for detection of label-free molecule ensembles in an interferometric configuration [18,19].…”

Michelson Interferometric Hydrogen Sulfide Gas Sensor Based on NH2-rGO Sensitive Film

“…When hydrogen sulfide gas is introduced, the interaction between the gas and sensing film causes a change of the effective RI of the TCF cladding. According to (8), ∆n will change with the shift in variation of the trough wavelength of the mth-order interference. GO dispersion (30 mL) and absolute ethanol (50 mL) were fully mixed together, and ammonia was slowly added to the mixed solution dropwise until pH = 10.…”

“…In recent years, optical fibre sensors have been widely used in environmental monitoring, such as that of biomolecules [6][7][8], gases [9][10][11], temperature and humidity [12][13][14], pH [15,16], etc. Among them, the Michelson interferometer (MI) has received much attention.…”

Up-down Taper Based In-Fiber Mach-Zehnder Interferometer for Liquid Refractive Index Sensing

“…Optical fiber refractive index (RI) sensors are used in biological fields, medicine and environment [1][2][3]. So far, lots of fiber optic RI sensors have been reported in the literature, such as Mach-Zehnder (MZIs) [4][5][6], Fiber Grating [7], Fabry-Pérot (FPIs) [8], Sagnac [9] and multi-mode interferometer [10][11][12]. Among them, Quan [8] prepared an open-cavity FPI by splicing a section of the fused silica fiber tube between photonic crystal fiber (PCF) and single mode fiber (SMF), an ultra-high sensitivity of 30,899 nm/RIU is obtained.…”