Distributed fiber optic sensing on optical fibers carrying traffic

An apparatus, comprising:

• an optical data transceiver having a first optical port for transmitting optical data communication signals to a near end of a first optical fiber line and a different second optical port for receiving optical data communication signals from a near end of a different second optical fiber line;
• and
• a distributed fiber optic sensing interrogator configured to transmit a distributed fiber optic sensing probe signal to the second optical fiber line via the second optical port and to detect a portion of the distributed fiber optic sensing probe signal backscattered in the second optical fiber line, wherein the distributed fiber optic sensing interrogator is configured to perform, based on the detected portion of the distributed fiber optic sensing probe signal backscattered in the second optical fiber line, distributed fiber optic sensing;
• and
• wherein the optical data communication signals are in a first wavelength band and the distributed fiber optic sensing probe signal is in a second wavelength band spectrally separated from the first wavelength band;
• wherein the first wavelength band is within a conventional optical telecommunication band (C-band) and the second wavelength band is within a long wavelength optical telecommunication band (L-band), and wherein the second wavelength band is at least 2 nm outside of the first wavelength band.