Extending DAS range in undersea cables using loopbacks
AssigneeSubcom, LLC
InventorsGeorg Heinrich Mohs, Alexei N. Pilipetskii
Life of this patent
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Abstract
Techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables are provided. For example, DAS range can be extended by transmitting and amplifying a DAS signal along multiple spans of a first optical fiber, routing or bypassing the DAS signal from the first optical fiber to a second optical fiber different from the first fiber via a high-loss loopback architecture, and returning and amplifying the DAS signal along the same multiple spans back to a DAS device. The DAS device may then receive and process the DAS signal to detect any changes in the DAS environment. The loopback configuration may be based on different types of loopback architecture.
Claims10
A system comprising:
- a plurality of optical fiber pairs in an undersea cable, each of said optical fiber pairs capable of carrying wavelength division multiplexed payload channels;
- one pair of the plurality of optical fiber pairs providing a bidirectional transmission path for an optical distributed acoustic sensing (DAS) signal wherein a first optical fiber of the one pair of optical fiber pairs providing a transmit path for the DAS signal to propagate in a first direction and a second optical fiber of the one pair of optical fiber pairs providing a return path for the DAS signal to propagate in second direction opposite the first direction;
- at least a first optical amplifier coupled to and disposed along the first optical fiber;
- at least a second optical amplifier coupled to and disposed along the second optical fiber;
- and
- a loopback fiber having a first end and a second end,
- wherein the first end of the loopback fiber is coupled, at a first coupling point, to the first optical fiber at an output of the first optical amplifier, and
- wherein the second end of the loopback fiber is coupled, at a second coupling point, to an input of the second optical amplifier at a second coupling point.
A method comprising:
- transmitting, by a distributed acoustic sensing (DAS) device, a DAS signal along a first optical fiber, said first optical fiber being part of a first fiber pair within an optical communications cable having a plurality of fiber pairs each capable of carrying wavelength division multiplexed payload channels;
- receiving, by the DAS device, the DAS signal via a second optical fiber, said second optical fiber being part of the first fiber pair within the optical communications cable having a plurality of fiber pairs, said first optical fiber of the first fiber pair carrying the DAS signal in a first direction along the optical communications cable and the second optical fiber of the first fiber pair carrying the DAS signal in a second direction opposite the first direction along the optical communications cable;
- and
- performing, by the DAS device, processing on the received DAS signal,
- wherein the transmitted DAS signal is routed or bypassed from the first optical fiber to the second optical fiber via a loopback fiber, the loopback fiber having a first end coupled to the output of a first optical amplifier disposed along the first optical fiber and a second end coupled to an input of a second optical amplifier disposed along the second optical fiber.
Dependencies are inferred from the claim text.