EP-4735836-A1 - METHOD AND/OR SYSTEM FOR REDUCING NUMBER OF REDUNDANT CABLE PATHS IN AN OPTICAL NETWORK

Abstract

Methods for reducing the number of redundant cable paths in a multi-path redundant fiber optic cable network are disclosed. A method includes: monitoring cable paths in the fiber optic cable network using distributed fiber optic sensing to detect cable break events; measuring cable break rates for the cable paths in the fiber optic cable network over a period of time based on the detected cable break events; determining availability of the fiber optic cable network over the period of time, the availability determined based on the number of redundant cable paths in the fiber optic cable network and the cable break rates of the cable paths; and providing an indication when the fiber optic cable network achieves a target availability with at least one less redundant cable path.

Inventors

• ENGLUND, MARK ANDREW
• Sokol, Mark

Assignees

• Fiber Sense Limited

Dates

Publication Date

20260506

Application Date

20240627

Claims (20)

1. 1. A method for reducing a number of redundant cable paths in a multi-path redundant fiber optic cable network, the method including: monitoring cable paths in the fiber optic cable network using distributed fiber optic sensing to detect cable break events; measuring cable break rates for the cable paths in the fiber optic cable network over a period of time based on the detected cable break events; determining availability of the fiber optic cable network over the period of time, the availability determined based on the number of redundant cable paths in the fiber optic cable network and the cable break rates for the cable paths in the fiber optic cable network; and providing an indication when the fiber optic cable network achieves a target availability with at least one less redundant cable path.
2. 2. The method of claim 1, further comprising: removing at least one redundant cable path from the fiber optic cable network in response to the indication.
3. 3. The method of claim 1 further including installing at least one DFOS system to monitor the cable paths of the fiber optic cable network.
4. 4. The method of claim 3, wherein monitoring the cable paths of the fiber optic cable network includes: repeatedly transmitting, at multiple instants, interrogating optical signals into at least one optical fiber associated with each cable path of the fiber optic cable network; and receiving, during an observation period following each of the multiple instants, returning optical signals scattered in a distributed manner over distance along the cable paths, the scattering influenced by acoustic disturbances caused by the multiple targets within the observation period.
5. 5. The method of claim 4, further comprising determining a cable break by: determining a probability of occurrence of predetermined phase difference values between successive samples of processed backscattered signals from the cables.
6. 6. The method of claim 5, wherein determining the probability of occurrence of the predetermined phase difference values between successive samples comprises generating a histogram of the phase difference values between successive samples and analyzing a shape of the histogram to detect existence or otherwise of a cable break event.
7. 7. The method of claim 6, further comprising determining a cable break event if the histogram has a substantially flat shape.
8. 8. The method of claim 4, further comprising determining the cable break event upon determining that disturbance events are detected in multiple consecutive locations along the optical fiber.
9. 9. The method of claim 4, further comprising determining the cable break event upon determining that disturbance events are detected in all locations along the optical fiber downstream from an originating location.
10. 10. The method of claim 1, wherein determining availability of the fiber optic cable network over the period of time comprises computing a full availability of the network minus a product of availability of individual cable paths of the network as - Availability = 1 — [(1 — Avail^ x (1 — Avail 2 ) X ... x (1 — Avail^] where n is the number of cable paths in the network and availn represents the availability of the n th path in the network and is computed as 1 -cable break rate of the n th path.
11. 11. The method of any one of the preceding claims wherein the fiber optic cable network is a telecommunications data network extending between at least two sites, which may include virtual private cloud sites.
12. 12. The method of any one of claims 4-11 further comprising: analyzing the returning optical signals associated with a period of time to determine whether a cable threat event is occurring in real time; and generating an interdiction causing alert upon determining that the cable threat event is occurring.
13. 13. The method of claim 12 further comprising: upon determining that the threat event is occurring: determining a location of the threat event; and assigning a threat level to the threat event depending at least on proximity of the threat event to an underground cable asset.
14. 14. The method of claim 13, wherein the interdiction causing alert is generated when the assigned threat level exceeds a threshold threat level.
15. 15. The method of any one of claims 12-14, wherein determining that the threat event is occurring and generating the interdiction causing alert results in a reduction in the cable break events over time through interdiction of the threat event.
16. 16. A method for reducing the number of redundant cable paths in an n-path redundant fiber optic cable network having a target availability, the method including: monitoring cable break-related events in the n cable paths in the fiber optic cable network in real-time using distributed fiber optic sensing; measuring cable break rates of the n cable paths over a period of time based on the monitored cable break-related events; computing availability of n-1 cable paths based on the measured cable break rates; and providing an indication when the fiber optic cable network achieves the target availability with the n-1 cable paths.
17. 17. The method of claim 16, further comprising: removing at least one redundant cable path from the fiber optic cable network in response to the indication.
18. 18. The method of claim 16 or 17 further including installing at least one DFOS system to monitor the cable paths of the fiber optic cable network.
19. 19. The method of claim 18, further comprising monitoring at least one of the n cable paths using the DFOS system to detect one or more threat events in real time and generate interdiction causing alerts in response to detecting the one or more threat events.
20. 20. The method of claim 18, further comprising achieving a reduction in the cable break rate in the at least one cable path in the fiber optic cable network over time as a result of generating the interdiction causing alerts and through interdiction of the threat event.

Description

METHOD AND/OR SYSTEM FOR REDUCING NUMBER OF REDUNDANT CABLE PATHS IN AN OPTICAL NETWORK TECHNICAL FIELD [0001] The present disclosure generally relates to systems and methods for distributed sensing using one or more optical fibers. More particularly, aspects of the present disclosure relate to systems and methods for reducing redundancy in optical fiber networks using distributed fiber optic sensing (DFOS). BACKGROUND [0002] Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and/or combined with other pieces of prior art by a skilled person in the art. [0003] The majority of optical cables and utility infrastructure across cities are buried in public spaces along shared access ways like roads and streets. This infrastructure is typically also buried alongside a range of other assets, such as sewers, gas mains, water mains, electricity cables, etc. Fig. 1 illustrates a schematic of an example underground cross-section 100 under and adjacent to a road 102 and sidewalk 103. As seen in the schematic, fiber optic cables 104 may be buried under the road 102, along with gas mains 106, water mains 108, and electricity cables 110. [0004] From time to time, the road 102 and/or the sidewalk 103 may be excavated to maintain, repair, or install new infrastructure underneath it. If these excavations are not conducted properly, they may damage or destroy one or more of the assets, such as the fiber optic cables 104. It will be appreciated that if a fiber optic cable is damaged or destroyed, it can drastically affect the ability of the cable to communicate data, and this can lead to catastrophic interruption to data services. [0005] To address this, most fiber optic networks build in network redundancy - i.e., they provide multiple, geographically diverse cable paths to service the same client site. This way, if a primary cable path servicing a client is damaged or destroyed, one of the secondary or alternative cable paths can be used to service the client without interruption. Generally, the more geographically diverse cable paths in a network, the more robust the network is to any isolated cable incidents. However, increasing redundancy in a network increases the infrastructure costs and service costs to clients that use the optical network. [0006] Accordingly, there exists a need for systems and methods that can aid in reducing network redundancy while maintaining the same level of data availability and uninteruptability. SUMMARY [0007] According to a first aspect of the present disclosure there is provided a method for reducing the number of redundant cable paths in a multi-path redundant fiber optic cable network. The method includes: monitoring cable paths in the fiber optic cable network using distributed fiber optic sensing to detect cable break events; measuring cable break rates for the cable paths in the fiber optic cable network over a period of time based on the detected cable break events; determining availability of the fiber optic cable network over the period of time, the availability determined based on the number of redundant cable paths in the fiber optic cable network and the cable break rates of the cable paths; and providing an indication when the fiber optic cable network achieves a target availability with at least one less redundant cable path. [0008] According to a second aspect of the present disclosure there is provided a method for reducing the number of redundant cable paths in an n-path redundant fiber optic cable network having a target availability, the method including: monitoring cable break-related events in the n cable paths in the fiber optic cable network in real-time using distributed fiber optic sensing; measuring cable break rates of the n cable paths over a period of time based on the monitored cable break-related events; computing availability of n-1 cable paths based on the measured cable break rates; and providing an indication when the fiber optic cable network achieves the target availability with the n-1 cable paths. Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. [0009] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0010] Fig. 1 is a schematic of an example road cross-section showing various assets buried under the road. [0011] Fig. 2 is a block diagram of an example system for reducing redundancy in a redundant multi path fiber optic netwo