Optical network element for WDM

摘要

An optical network element comprises:
an optical input (10),
a distributing component (14) arranged to pass optical signals from the optical input to an optical transit path (16) and to an optical drop path (23),
a drop module (20) comprising a wavelength demultiplexing arrangement (22) connected to the optical drop path (23) and a plurality of optical receivers (21) for demodulating optical signals,
an add module (30) comprising a wavelength multiplexing arrangement (32) connected to an optical add path (33) and a plurality of optical transmitters (31), and
an optical loop back path (140) connecting the add module to the drop module for passing optical signals generated by the transmitters of the add module to the receivers of the drop module for the purpose of testing.
Application to testing of transmitters, receivers and the optical add and drop modules of an optical network element and to maintaining accurate alarm surveillance.