Guest Editor's Desk

Abstract

Fiber Optic Sensors and Applications

Fiber Optic Sensors have become extremely popular in the recent times owing to many advantages such as immunity to Electro Magnetic Interference, high band width, low cross talk, chemical inertness, compact foot-print, multi-modal & multi-point sensing capability, etc. In addition, they also serve to communicate the sensed data over longer distances without any loss. Further, the ready availability of a large number of components from the mass produced fiber optic communication industry and relatively few fabrication steps have made fiber optic sensors widely deployable.

Fiber optic sensors generally work on the principle of phase or intensity modulation of the light transmitted through the fiber which is caused by an external perturbation. These sensors are typically used for sensing temperature or strain in basic form and with precise transduction techniques, they have found extended use in sensing parameters like displacement, vibration, pressure, acceleration, rotation, chemical concentrations, etc. This special issue attempts to provide an overview of the recent developments in the area of fiber optic sensors.

In this issue, the article by Rahman et al. deals with the design and optimization of novel optical sensors. It presents some selected results illustrating the value and potential of the numerically efficient finite element method in the design of systems. The paper by Asundi details the “on-line condition monitoring”of civil structures, using fiber optic polarimetric sensors, which has emerged as an attractive alternative to the traditional preventive maintenance. The contribution of Prabhathana and Murukeshan reviews different waveguide-based architectures for label-free detection of bio-molecules. The working principlesof various sensor configurations and the use of a silicon waveguide Bragg grating resonator array as ahighly sensitive refractive index sensor have been described.

The paper by Bishnu Pal attempts to review the basic principles that underpin the area of fiber optic sensing with a few illustrative examples of applications. Thyagarajan and Gupta, in their article, have presented the recent work on super imposed Long Period Grating designs which show very interesting transmission characteristics; with appropriate design, long period gratings are expected to find applications as wavelength filters, sensors, channel isolation filters and wavelength interrogators.

Sharath Umesh et al., in their paper, have provided a brief overview of the recent applications offiber Bragg grating sensors in biomechanical, bio-sensing and bio-medical fields. The article of Balaji Srinivasan et al. describes the elastic wave sensing using fiber Bragg grating-based sensors and dynamic interrogators. It discusses the directional response of FBG-based sensors and their role in the unique identification of different Lamb modes based on the dispersion characteristics.

The paper by Umesh Tiwari presents the recent research and development activities in structural health monitoring with fiber Bragg grating sensors. It also describes some of the strain-temperature discrimination techniques proposed recently. The contribution of Tushar Biswas et al. deals with plasmonic micro-structured optical fibers and their application in bio-sensing. It presents a very simple design of metal embedded hollow-core photonic crystal fiber for efficient sensing of very low refractive index which can find potential application in bio-sensing.

I am hopeful that this special issue elicits the recent advancements in the area of fiber optic sensorsand related fields.