Fiber-optic sensor applications

Radhakrishnan J, El-Sherif MA (1996) Analysis on spatial intensity modulation for fiber optic sensor applications. J OptEiber Technol 2 114-126... 

Industrial Applications Gel coating/gel monolith for fiber-optic sensor applications ultrathin films ... 

Peterson J.I., Vurek G.G., Fiber-optic sensors for biomedical applications, Science 1984 224 123. 

Tennyson, R.C., Morison, D., Colpitts, B., and Brownn, A. Application of Brillouin fiber optic sensors to monitor pipeline integrity IPC2004, Paper 0711, Calgary, October 2004. 

Newer techniques for measuring the refractive index allow for instantaneous, real-time measurement in process streams, or alternatively, a special continuous-flow sample well can be installed on bench top instruments. Small, pocket-sized refractometers also make held measurement very simple and reliable. Fiber optic sensors find uses in biomedical applications. 

It is already over two decades since the first concepts of the use of fiber optic techniques for sensor purposes were discussed. The initial drive for the development of fiber optic sensors came from their potential use in military and aerospace applications where the cost factors of the introduction of new technology were less rigid and the working environment more hostile than is experienced with other areas of application. 

Perhaps the first detailed discussion of such a technique in fluorescent thermometry (shown in Figure 11.10) was given by Zhang et al. in their work(36) based on both mathematical analysis and experimental simulation. Examples of the electronic design of the corresponding system and the application of the technique in a ruby fluorescence-based fiber-optic sensor system are also listed. This shows that there is no difference in the measurement sensitivity between a system using square-wave modulation and one using sinusoidal modulation. However, the former performs a little better in terms of the measurement resolution. 

Optical Fibers. Pure and doped fused silica fibers have replaced copper lines in the telecommunication area. Fused silica fibers are used in laser surgery, optical sensor application, and laser welding (see Sensors). Optical-fiber-tethered weapons such as fiber-optics-guided (FOG) missiles are another potential application for fused silica (249,250) (see Fiber optics). 

Sampling with fiber optic sensors can be continuous if needed otherwise they can be operated discontinuously, with a lower duty cycle. These sensors could be used for laboratory-based or in situ applications. The cost of instrumentation for fiber optic systems should be 25,000 to 50,000. Sensors would need to be replaced periodically (several weeks to many months), depending upon their design. Sensors using fiber optic probes will be available within 5 years for some applications and within 10 years for some others. Sensors for pH, C02, and 02 are in development now new sensors should be capable of measuring from high concentrations down to 1 part per million for ions and organic materials. Basic research is still required for specific applications. 

Adrian, P. Technical Advances in Fiber-Optic Sensors Theoiy and Applications, Sensors 23 (September 1991). 

Peterson, J.I. and G.G. Vurek Fiber-Optic Sensors for Biorredical Applications, ... 

Fiber optic sensors are an alternative to thermocouples as embedded temperature distribution mapping sensors. As described in Section 2.2.7, McIntyre et al.104 developed two distinct fiber optic temperature probe technologies for fuel cell applications (free space probes and optical fiber probes). Both sensor technologies showed similar trends in fuel cell temperature and were also used to study transient conditions. 

The operation of proximity sensors can be based on a wide range of principles, including capacitance, induction, Hall and magnetic effects variable reluctance, linear variable differential transformer (LVDT), variable resistor mechanical and electromechanical limit switches optical, photoelectric, or fiber-optic sensors laser-based distance, dimension, or thickness sensors air gap sensors ultrasonic and displacement transducers. Their detection ranges vary from micrometers to meters, and their applications include the measurement of position, displacement, proximity, or operational limits in controlling moving components of valves and dampers. Either linear or angular position can be measured ... 

The application as optical sensor is possible based on sensitive films containing thioether moieties which exhibit changes in optical absorption when probed by guided light. Moreover, by combination with the fiber coating material described above (Fig. 2) the potential for fabrication of fiber optical sensors is evident. 

Fiber-optic sensors have been reported in literatures since 1970s. They have since then been used in chemical [1 ], biochemical [5-8], biomedical and environmental [9-12] sensors applications. 

The intention of the author of this chapter was to provide an introductory knowledge base on the application of fiber optics in chemical and biosensors. The field of fiber-optic sensors is progressing very rapidly, with significant new research being continuously reported for various sensors applications. 

In this chapter, a general introduction to fiber-optic sensors is presented, followed by sections on the principle of sensors design and sensors development and processing, as well as on sensors characterization and optimization. The technical feasibility and viability of fiber optics in chemical and biosensors applications have been demonstrated with a number of examples and a list of references on successfully reported research. Also, an overview on state-of-the-art research is presented, which is still under development and requires more work before the ultimate limits imposed by fiber optics science and technologies are reached. 

Krohn, D. A. (1988) Fiber Optic Sensors - Fundamentals and Applications, Research Triangle Park, NC Instrument Society of America. 

Fiber-optic sensors are less expensive, more rugged, and smaller than electrodes in the future we may see the former replacing the latter in various areas of analytical and clinical chemistry. Fields of application include environmental monitoring, process control, remote spectroscopy in high-risk areas with radioactive, explosive, biological, or other hazards, titrimetry, and in-vivo bioanalysis. 

Xu W, Schmidt R, Whaley M, Demas J N, DeGraff B A, Karikari E K and Farmer B L 1995 Oxygen sensors based on luminescence quenching interactions of pyrene with the polymer supports Anal. Chem. 67 3172-80 Peterson J I, Goldstein S R, Fitzgerald R V and Buckhold D K 1980 Fiber optic pH probe for physiological use Anal. Chem. 52 864-9 Peterson J 1 and Vurek G 1984 Fiber-optic sensors for biomedical applications Science 123 123-7... 

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