| 摘要 |
A device for measuring a measured optical transmission path includes a first optical transmitter transmitting into the measured optical tramsmission path and a compensation transmitter transmitting into a compensation optical transmission path. The device includes an optical receiver for receiving transmissions from each of the first optical transmitter and the compensation transmitter. A controller controls the compensation transmitter and provides a controller output signal representative of a measured value of the first transmission path. A nose piece separates the optical transmitter from the optical receiver. The compensation transmitter is placed in a first cavity. The receiver is placed in a second cavity. A filter in the measured optical transmission path has a transmissivity for the wavelength of the light of the first optical transmitter of at least 50% and an absorption factor for the wavelength of the light of the compensation transmitter of at least 25%. |
