Neutral path optical measurement arrangement for physical valve - has bidirectional transmission path, modulator and absorptive or dispersive optical switching element

摘要

An optical measurement arrangement has a light source (2) and receiver (4) connected via a bidirectional transmission path to an optical measurement transducer which modulates the light under the influence of the measurement parameter and couples it back into the transmission path. An absorptive or dispersive (10) optical switching element associated with the measurement transducer (20) to derive a reference signal has an optical control input and is arranged in parallel or series with the transmission path (8) respectively. ADVANTAGE - Can measure a physical value practically independently of losses in optical transmission path.