Systems and methods are disclosed, including an optical switching system comprising an upstream optical signal detector between a first node and a second node configured to detect optical signals from the second node and to switch data traffic from a working path to a protecting path when optical signals from the second node are indicative of a failure in the working path; wherein the first node is configured to transmit data traffic in first optical signals with wavelengths in channels in a first band and receive the data traffic in second optical signals with wavelengths in channels in a second band from the second node; and one or more optical filter, between the second node and the upstream optical signal detector, configured to block signals with wavelengths in the first band that are reflected because of a break in the path between the optical filter and the second node.