Theory of Spectral Encoding for Fiber-Optic Sensors

A variety of fiber-optic sensors for industrial applications use the scheme of spectral encoding. They represent the measurand by spectral features of the light that is transmitted by a fiber link from the transducer to a receiver unit. Their general advantages are a reduced sensitivity to variations of the link losses and an interchangeability of transducers without recalibration. An analysis of this encoding scheme is given from a system’s point of view. Transmission of information from the measurand to the evaluation unit is treated as occurring on a number of discrete spectral channels. Decoding is performed by channel selection and by channel interpolation. The maximum attainable resolution is determined from the power budget of the sensor, distinguishing between scanning and tracking operation and systems with array detection. Finally, the immunity to variation of losses is discussed.

[1]  M. Brenci,et al.  Optical Fiber Thermometer For Medical Use , 1984, Optics & Photonics.

[2]  R Ulrich,et al.  Fiber-optic angular sensor with interleaved channel spectra. , 1986, Optics letters.

[3]  R. Ulrich,et al.  High-Accuracy Position-Sensing With Fiber-Coupled White-Light Interferometers , 1984, Other Conferences.

[4]  G. Beheim,et al.  Remote displacement measurement using a passive interferometer with a fiber-optic link. , 1985, Applied optics.

[5]  P. Cielo,et al.  Fiber optic hydrophone: improved strain configuration and environmental noise protection. , 1979, Applied optics.

[6]  Mischa Schwartz,et al.  Information transmission, modulation, and noise , 1959 .

[7]  T H Barnes.  Photodiode array Fourier transform spectrometer with improved dynamic range. , 1985, Applied optics.

[8]  Anna Grazia Mignani,et al.  Thermochromic Transducer Optical Fiber Temperature Sensor , 1984, Other Conferences.

[9]  J. A. Decker.  Chapter 5 – Hadamard-Transform Spectroscopy , 1977 .

[10]  M. C. Hutley.  Wavelength Encoded Optical Fibre Sensors , 1984, Other Conferences.

[11]  Irene A. Stegun,et al.  Handbook of Mathematical Functions. , 1966 .

[12]  V. E. Wood.  Table errata: Handbook of mathematical functions with formulas, graphs, and mathematical tables (Nat. Bur. Standards, Washington, D.C., 1964) edited by M. Abramowitz and I. A. Stegun , 1969 .

[13]  N. L. Jarvis,et al.  Reversible optical waveguide sensor for ammonia vapors. , 1983, Optics letters.

[14]  W. G. Fateley,et al.  Hadamard Transform Spectroscopy , 1980 .

[15]  Emil Wolf,et al.  Principles of Optics: Contents , 1999 .