Wavelength-modulated fibre optical sensors

B. E. Jones and R. C. Spooncer, An optical fibre pressure sensor using a holographic shutter modulator with two wavelength intensity referencing, SPIE Proc. 514, 223 (1984). 

The construction of the optoelectronic interface can be based on a silicon photodiode since analytical and reference wavelengths are from the visible and the IR regions, respectively. The signals can be filtered out by optical filters (then two photodiodes are required) or one photodiode can be synchronised with modulation waves of the LEDs used. Finally, silica optical fibres can be used as light waveguides. The choice between single fibre or bundle is determined by the application of the sensor. 

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