Abstract
Single mode fibers are used for sensing when extreme sensitivity is required or when a well defined polarization of light is needed at a remote sensing point. Most sensors which use single mode fibers are of the intrinsic type (i.e. the action of the measurand on the light occurs within the fiber itself). The sensitivity advantage of single mode fibers arises because they permit the user to construct guided wave interferometers directly from the fiber itself so as to measure small phase changes in light transmitted through the measuring region. This is achieved by comparing the phase of a light wave which has traversed a sensing path with the phase of another light wave originating from the same source but arriving via a protected, reference path. The phase difference can be measured with a sensitivity of ∼10-6 of a wavelength [1] and the pathlength for the measuring interaction can be millions of wavelengths long. This leads to a possible measurement resolution for the optical path of one in 1012! Simultaneously, the absence of free space optical paths between sources and detectors eliminates slow alignment drifts which could easily occur if bulk-optical interferometers had been used. In practice, single mode fiber sensors tend to need very stable, highly coherent sources with low phase noise in order to gain full advantage of their potential sensitivity. When such sources are used, absolute calibration of phase difference is normally not possible and a range limit arises from the periodic nature of the interferometer output. These points will be explained later in this chapter. Recently, both of these problems have been avoided by using sources emitting in a broad wavelength range, with some compromise regarding the ultimate sensitivity achievable with any particular sensor. The concluding part of the chapter will be devoted to such sensors. Another important point to understand is that this type of sensor ultimately measures optical pathlength. Anything which changes the pathlength will therefore produce a signal. Since there are a multitude of effects which can affect the optical pathlength through a fiber, great care must always be taken to reduce or to compensate for these unwanted changes.
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References
Jackson, D. A., Dandridge, A. and Sheem, S. K. (1980) Measurement of small phase shifts using a single mode optical fibre interferometer. Optics Lett., 5, 139.
Tatam R. P., Pannell, C. N., Jones, J. D. C. and Jackson, D. A. (1987) Full polarisation state control utilising linearly birefringent monomode optical fibre. J. Lightwave Technol., LT-5(7), 980.
Tolansky, S. (1973) An Introduction to Interferometry. Longman, London.
Petuchowsky, S. J., Giallorenzi, T. G. and Sheem, S. K. (1981) A sensitive fibre optic Fabry Perot interferometer. IEEE J. Quant. Electron., QE-17, 2168.
Kersey, A. D., Jackson, D. A. and Corke, M. (1983) A simple fibre Fabry Perot sensor. Optics Commun., 45, 71.
Stokes, L. F., Chodorow, M. and Shaw, H. J. (1983) Sensitive all-single-mode-fiber resonant ring interferometer. IEEE J. Lightwave Technol., LT-1, 110.
Meltz, G., Morey, W. W. and Glenn, W. H. (1989) Formation of Bragg gratings in optical fibers by a transverse holographic method. Optics Lett., 14, 823.
Yariv, A. (1975) Quantum Electronics, 2nd edn., Wiley, London.
Jackson, D. A., Priest, R., Dandridge, A. and Tveten, A. B. (1980) Elimination of drift in a single mode optical fibre interferometer using a piezoelectrically stretched coiled fibre. Appl. Optics, 19, 2926.
Fritsch, K. and Adamasky, G. (1981) Simple circuit for feedback stabilisation of a single mode optical fibre interferometer. Rev. Sci. Instrum., 52, 996.
Dandridge, A., Tveten, A. B. and Giallorenzi, T. G. (1982) Homodyne demodulation scheme for fibre-optic sensors using phase generated carrier. IEEE J. Quant. Electron., QE-18, 1647.
Sheem, S. K., Giallorenzi, T. G. and Koo, K. P. (1982) Optical techniques to solve the fading problem in fibre interferometers. Appl. Optics, 21 689.
Kersey, A. D., Jackson, D. A. and Corke, M. (1983) Demodulation scheme for interferometric sensors employing laser frequency switching. Electron. Lett., 19, 102.
Koo, K. P., Tveten, A. B. and Dandridge, A. (1982) Passive stabilisation scheme for fibre interferometers using (3 × 3) fibre directional couplers. Appl. Phys. Lett., 41, 616.
Cole, J. H., Danver, B. A. and Bucaro, J. A. (1982) Synthetic heterodyne interferometric demodulation. IEEE J. Quant. Electron., QE-18, 694.
Jackson, D. A., Kersey, A. D., Corke, M. and Jones, J. D. C. (1982) Pseudo-heterodyne detection scheme for optical interferometers. Electron. Lett., 18, 1081.
Voges, E., Ostwald, O., Schiek, B. and Neyer, A. (1982) Optical phase and amplitude measurements by single sideband homodyne detection. IEEE J. Quant. Electron., QE-18, 124.
Kim B. Y. and Shaw, H. J. (1984) Phase reading all fiber-optic gyroscope. Optics Lett., 9, 378
Leilabady, P A., Jones, J. D. C., Corke, M. and Jackson, D. A. (1986) J. Phys. E: Sci. Instrum., 19, 143.
Webb, D. J., Jones, J. D.C, Taylor, R. M. and Jackson, D. A. (1988) Extended range monomode fibre-optic sensors: spectral and polarisation techniques. Int. J. Opto-electron., 3(3), 213.
Hocker, G. B. (1979) Fiber-optic sensing of pressure and temperature. Appl. Optics, 18(9), 1445.
Giallorenzi, T. G., Bucaro, J. A., Dandridge, A. et al. (1982) Optical fiber sensor technology. IEEE J. Quant. Electron., QE-18(4), 626.
Bergh, R. A., Lefevre, H. C. and Shaw, H. J. (1984) An overview of fibre-optic gyroscopes. J. Lightwave Technol., LT-2(2), 91.
Dyott, R. B. (1978) The fibre optic Doppler anemometer. IEE J. Microw. Optics Acoust., 2, 13.
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Handerek, V. (1995). Single mode optical fiber sensors. In: Grattan, K.T.V., Meggitt, B.T. (eds) Optical Fiber Sensor Technology. Optical and Quantum Electronics Series, vol 1. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1210-9_7
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DOI: https://doi.org/10.1007/978-94-011-1210-9_7
Publisher Name: Springer, Dordrecht
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