← Back to Gallery

Session: Technological Innovation [Poster]

Type: Poster

Date: 10/13/2026

Time: 05:00 PM

Room: Keauhou I- II

Optical Sensing and Communications Co-existence in Optically Amplified Fibre Links

Optical fibre networks provide an interesting established infrastructure for optical seismology, with fibres often embedded in the ground or on the seabed, and so are able to sense seismic events through an optical technique called distributed acoustic sensing (DAS). In many cases, these fibres are primarily for carrying data, and fibre infrastructure companies are unwilling to accommodate optical sensing channels that may disrupt existing data channel allocations. An emerging approach is to place the DAS channel in an optical waveband far from the data waveband, to ensure that the powerful optical pulses used in optical sensing are not able to interact a) with the optical amplifiers used in long links, or b) nonlinearly via disturbing the material properties of the fibre. With the DAS channel in a separate waveband, it is known that there are no interactions. Whether these effects are significant with strong DAS pulses and data signals in the same waveband is not immediately obvious.

Here we perform experiments in installed fibre in a metropolitan area that show that it is possible to transmit an optical sensing pulse, both co- and counter-propagating with high-speed optical signals, in a channel in the same waveband with no effect on the data signal. We compare this to operating in separate bands and see no change in behaviour. We then engineer a situation where the communications signal was able to be affected by the sensing light by cross-gain modulation in an optical amplifier. This occurred where only a single optical data channel was present and co-propagating with the sensing channel and were in the same band. This shows that there is a potential failure mode for optical sensing and optical data co-existence within optical fibre systems, but can be avoided by using default set-up techniques for running optical communication systems with optical amplifiers. We hope that this helps provide telecommunication providers with some confidence that DAS systems can be used in live optical fibres with no detriment to the commercial data carried in these systems.

Presenting Author: Luke

Additional Authors