Optical measuring apparatus

Claim 1

An optical measuring apparatus comprising an optical sensor which is connected to an optical coupler via an optical delay line and an optical path, which coupler is connected to an electro-optical transducer unit by a connecting fibre, which transducer unit supplies and receives light pulses and which supplies voltage pulses whose amplitudes correspond to the intensities of the received light pulses to a measuring circuit via at least one electrical line, which measuring circuit determines the physical quantity detected by the optical sensor from said amplitudes and transfers the result to a display, characterized in that the optical sensor comprises a polarisation splitter which receives light pulses from the optical path and from the optical delay line and which polarises the light pulses linearly in such a way that the planes of polarisation of the light pulses issuing from the optical path and from the optical delay line extend perpendicularly to each other, which polarisation splitter is followed by a sensor body which is traversed by the polarised light pulses, which changes the state of polarisation of the light pulses depending on the physical quantity which acts on the sensor body, and which reflects the light pulses back to the polarisation splitter by means of a mirror arranged on that side of the sensor body which is remote from the side where the light is incident, which polarisation splitter extracts a first linearly polarised light component from each light pulse to couple this component into the optical delay line and which extracts a second linearly polarised light component whose plane of polarisation extends perpendicularly to that of the first light component and couples it into the optical path.