Patent ID: 9723385
Date: 2017-08-01
CPC Classifications: H04B,H04J,H04Q

Claim:
1. A system comprising at least one network terminal, each such network terminal including: a switch to which a plurality of WDM signals are applied, each WDM signal including multiple wavelength channels; an optical channel monitor configured to optically monitor, in the optical domain, acceptability of one of the WDM signals; and a controller arranged to operate the switch such that the switch (a) selects at least one wavelength channel from at least one of the plurality of WDM signals and (b) outputs, at an output of the network terminal, the at least one wavelength channel to a port module external to the network terminal, wherein the optical channel monitor provides a signal to the controller based on the optical monitoring, wherein the port module provides a signal to the controller by performing electrical monitoring in the electrical domain of the wavelength channel outputted thereto at the output of the network terminal, wherein the controller operates the switch such that the switch selects the at least one wavelength channel based on (1) the signal provided by the port module and (2) the signal provided by the optical channel monitor, wherein the controller determines (1) based on the signal provided by the port module, whether the electrical monitoring indicates a signal level below a predetermined optical power threshold, and (2) based on the signal provided by the optical channel monitor, whether the optical monitoring indicates a signal level below a predetermined optical power threshold, and wherein the controller operates the switch such that, if it is determined that the electrical monitoring indicates a signal level below a predetermined optical power threshold or the optical monitoring indicates a signal level below a predetermined optical power threshold, the switch selects a wavelength channel, from at least one of the plurality of WDM signals, different from the selected at least one wavelength channel.