In-Service Optical Fault Isolation Using Counter Timestamps
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Solution Overview
Problem
Conventional optical fault isolation methods in optical networks are time-consuming, costly, and require external equipment, making it difficult to detect and isolate events such as fiber cuts and polarization transients in-service, especially when events are transient or occur randomly.
Innovation Solution
Implementing counters in Optical Transport Network frames that increment with each frame, allowing for in-service fault isolation by determining the location of events based on time differences between counters, without the need for external equipment, using the propagation speed of optical fiber to convert time differences into distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault isolation methods are used, then external equipment can detect events, but the process is time-consuming and requires subsequent event occurrences
Solution Approach 1:
The patent applies preliminary action by pre-positioning counters at each span within the optical network that continuously increment and record event timestamps. This preliminary recording capability eliminates the need for external equipment and subsequent event occurrences, allowing immediate fault location determination when an event is detected by comparing counter values and calculating time differences.
2Reliability
If external equipment is used for fault detection, then events can be detected, but the system complexity and cost increase
Solution Approach 1:
The patent implements self-service by enabling the optical network to detect and locate faults using its own internal counters and timing mechanisms. Each span's counter independently records event timestamps, and the system automatically calculates fault location by comparing these internal records, eliminating dependence on external OTDR equipment and reducing system complexity.
3Measurement precision
If conventional span-by-span isolation is used, then events can be detected, but the isolation process is costly and requires multiple events
Solution Approach 1:
The patent replaces the mechanical/manual process of span-by-span isolation with an automated electronic system. Counters at each span electronically record event timestamps, and a processor automatically compares these values to calculate precise fault locations, replacing costly and time-consuming manual isolation procedures with rapid computational analysis.
4Ease of operation
If in-service fault isolation is implemented, then operations continue during fault detection, but precise location determination requires sophisticated timing mechanisms
Solution Approach 1:
The patent applies segmentation by dividing the optical network into discrete spans, each with its own independent counter. This segmentation allows in-service operation since each span operates autonomously and records events independently. The timing mechanism complexity is reduced by using simple incrementing counters at each span rather than a centralized complex timing system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick and accurate localization of faults to within hundreds of meters, allowing for immediate isolation of transient events without subsequent occurrences, reducing the need for external equipment and enabling end-to-end monitoring of optical links.
Implementation Method 1
converting time differences between the counters into distance, based on propagation speed of a signal over optical fiber forming the link
Data Source
AI summary
Systems and methods for in-service optical fault isolation on a link between a first node and a second node include transmitting counters between each of the first node and the second node; determining associated values for the counters responsive to an event associated with the link; and determining a location of the event based on the associated values for the counters. The determining includes converting time differences between the counters into distance, based on propagation speed of a signal over optical fiber forming the link. The location is determined in-service based on a single occurrence of the event without external equipment.