Segmented detection SPR sensor based on seven-core fiber

Abstract

By using a seven-core fiber (SCF), we propose and demonstrate a novel segmented detection SPR sensor, which solves two bottlenecks about the fiber SPR sensor of low sensitivity and the difficulty in the multichannel detection. The proposed sensor has ultra high sensitivity and wide detection range because of employing the segmented detection technology. Besides that, the proposed sensor employs reflection-type time division multiplexing (TDM) technology in fiber multichannel detection for the first time. We couple light into and out of the six circularly symmetric distributed cores of the seven-core fiber to realize the three channel SPR sensing and testing. This three-channel SPR sensor has the advantages of detecting biochemical or multi analytes reactions and eliminating the distractions due to temperature fluctuations or sample composition variations and adsorption of non-target molecules to the sensor surface. This SPR sensor also has the advantages of online monitoring by inserting into the blood vessel because of its small size. Furthermore, this paper has deeply researched the relationship between the refractive index of the solution to be measured, the grinding angle of the sensing channel, the sensitivity and the detection range. In this paper, we propose a novel segmented detection method which realizes the wide detection range with the wider refractive index range of 1.333~1.395 and the narrower working bandwidth of 250nm compared with the common SPR sensor, the average sensitivity and the maximum sensitivity of the sensor reach 7387.1nm/RIU and 8502.5nm/RIU respectively.

A Polarization-Independent Fiber-Optic SPR Sensor

“…Figure 5 b provides the relation between the refractive index of sample and the refractive index dependent sensitivity. Figure 5 indicates that the sensitivity and the resonant wavelength increase as the refractive index increases, which are in accordance with the conclusions in the literature [ 2 ]. According to the testing results, the maximum sensitivity is up to 4392 nm/RIU.…”

“…When the momentum of the incident light match that of surface plasmon wave, a sharp resonant dip occurs in the reflected light intensity. The propagation constant of the SPW strongly depends on the refractive index of the surrounding medium adjacent to the metal layer, therefore, SPR sensors have become among the most wide spread in their applications to disease diagnostics, food safety, environmental monitoring, and biomolecular interactions analysis in recent years [ 1 , 2 ]. Traditionally, the resonant condition is related to the incident angle or wavelength, and it is also critical for SPR to provide the right polarization.…”

“…Since Jorgenson and Yee proposed fiber-optic SPR sensor decades ago, many new types of fiber-optic SPR sensor have been increasingly developed possessing the advantages of small size, allows for a smaller sample volume, easy to be integrated [ 2 , 3 ]. Typically, flat metal layers are used in bulk optical Kretschmann configuration where polarizing devices are used to provide TM-polarized incident light with respect to the incident plane without ambiguity.…”

Optical Fiber Cladding SPR Sensor Based on Core-Shift Welding Technology

“…For the common silica cladding optical fiber, the evanescent field exists in the interface between the fiber core and the cladding because the cladding wraps the fiber core, and the transmission of light between the fiber core and the cladding has total reflection. In order to contact the evanescent field with the gold film, some of the traditional methods to peel off the cladding of the fiber are hydrofluoric acid (HF) corrosion [3,4], polish-grinding on the side face of the fiber [5,6,7,8], and grinding on the end face of the fiber [9,10,11,12]. The fiber core is exposed to the air, and the evanescent field exists in the interface of the fiber core and the air.…”

Surface-Plasmon-Resonance-Based Optical Fiber Curvature Sensor with Temperature Compensation by Means of Dual Modulation Method

“…Compared to other optical fiber sensors based on FBG, LPFG, optical fiber interferometer (OFI) and so on, the SPR fiber sensors have more excellent performances such as ultrahigh sensitivity up to several microns per RIU. This means the SPR fiber sensors have a smaller detection limitation under the same wavelength resolution of detector [ 18 ]. However, in the fields of the physical parameters measurement, such as curvature and displacement measurement, the applications of the SPR fiber sensor are still scarce because there are some barriers to control the propagation angle of the light beam in the fiber and the intensity of the evanescent wave.…”