Abstract
A novel multi-channel fiber optic surface plasmon resonance (SPR) sensor is reported. The sensing structure consists of a single-mode optical fiber, covered with a thin gold layer, which supports a surface plasmon (SP), and a Bragg grating. The Bragg grating induces coupling between the forward-propagating fundamental core mode and the back-propagating SP-cladding mode. As the SP-cladding modes are highly sensitive to changes in the refractive index of the surrounding medium, the changes can be accurately measured by spectroscopy of these hybrid modes. Multichannel capability is achieved by employing a sequence of Bragg gratings of different periods and their reading via the wavelength division multiplexing. Theoretical analysis and optimization based on the coupled-mode theory (CMT) is carried out and performance characteristics of the sensor are determined.
Highlights
Over the past decade, surface plasmon resonance (SPR) sensors have become a powerful tool for biomolecular research and affinity biosensing [1]
An alternative approach to excitation of SPs in fiber optic structures has been reported which consists of the coupling of a core mode of a single-mode optical fiber with a long-period grating [8] or a Bragg grating [9] to an SP-coupled-cladding mode
We propose a fiber optic SPR sensor based on spectroscopy of back-propagating SP-cladding modes which are excited by a guided core fiber mode via a Bragg grating
Summary
Surface plasmon resonance (SPR) sensors have become a powerful tool for biomolecular research and affinity biosensing [1]. An SPR sensor based on a side-polished polarization-maintaining single-mode fiber was developed to suppress the sensitivity of the fiber to deformations [7]. We propose a fiber optic SPR sensor based on spectroscopy of back-propagating SP-cladding modes which are excited by a guided core fiber mode via a Bragg grating. In this sensor, spectrum of the transmitted light is measured and changes in the refractive index of analyte are observed as a spectral shift of the transmission dips associated with the excitation of SP-coupled-cladding modes. Theoretical analysis and optimization of the sensing structure is carried out by means of the coupled-mode theory (CMT)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
