FIBRE-OPTIC CURRENT SENSOR Russian patent published in 2011 - IPC G01R15/24 G02B6/00 

FIELD: physics.

SUBSTANCE: fibre-optic current sensor has optically connected optical radiation source, a splitter, whose second input is connected through a photodetector to a signal processing unit, a fibre polariser, a fibre filter, a modulator, a fibre delay line, a quarter-wave plate and a sensor head around a current conductor, said sensor head being made from optical fibre which supports circular polarisation. The signal processing unit has a reference generator, a demodulator, an analogue-to-digital converter and a digital-to-analogue converter, an adder, a stepped saw-tooth signal former, a square-wave signal former and a comparator unit. The signal input of the analogue-to-digital converter forms the input of the signal processing unit connected to the output of the photodetector. The output of the digital-to-analogue converter forms the output of the signal processing unit connected to the control input of the modulator. The data output of the stepped saw-tooth signal former forms the data output of the signal processing unit which is the output of the current sensor. The output of the analogue-to-digital converter is connected to the signal inputs of the demodulator and the comparator unit. The output of the demodulator is connected to the signal input of the stepped saw-tooth signal former. The output of the comparator unit is connected to correcting inputs of the square-wave signal former and the stepped saw-tooth signal former.

EFFECT: high accuracy and wide measurement range.

3 cl, 1 dwg