Monitoring of optical broadband connection lines up to a passive interface

摘要

In an optical waveguide connection unit, a pilot tone signal is added to the electric control signal of the electro-optical transducer, and a small part of the optical signal is branched off at the passive interface and transmitted back to the connection unit where it is fed jointly with the optical signal received from the distant end to the opto-electrical transducer; The pilot tone signal component contained in the electric received signal is subjected to a single-stage or multi-stage threshold discrimination, the result of which provides a measure of the quality of the optical connection line between the connection unit and the passive interface.