Method and system for detecting loss of signal in wavelength division multiplexed systems

摘要

A method and system for unambiguously detecting fiber cuts in an optical network regardless of the number of EDFAs that are located between the fiber cut and the monitor point. In accordance with our invention, the power of a marker wavelength is compared to the power of a nearby spectral region. Where the comparison indicates that the power ratio is approximately equal to unity a flag is raised indicating that there is fiber cut. Where the comparison indicates that the power ratio is much greater than unity the flag is not raised. The monitoring point includes circuitry for detecting the ratio between the marker wavelength and the nearby spectral band and for indicating when there is a fiber cut.