Optical Span Fault Localization Using Amplifier Backscattering
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Solution Overview
Problem
Existing methods for fault localization in optical fiber networks, such as using optical time domain reflectometers (OTDR), are expensive and complex, necessitating a more cost-effective and efficient approach.
Innovation Solution
Utilize power monitoring devices already present in optical amplifiers to detect reflected signals from Rayleigh backscattering, combined with optical circulators or power splitters, to accurately locate faults in optical fiber spans without additional modulation, enhancing accuracy by using signals from both ends of the span.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical time domain reflectometers are installed at each network element for automatic fault localization, then fault localization accuracy is improved, but system cost increases significantly
Solution Approach 1:
The patent makes existing optical amplifiers self-serve dual functions: their primary amplification role plus a secondary fault detection role. By utilizing the inherent Rayleigh backscattering monitoring capability already present in EDFAs and adding only simple optical circulators and power meters, the system enables each amplifier to locally detect faults without requiring external OTDR equipment at every node.
Solution Approach 2:
The patent transforms optical amplifiers into multi-functional devices that simultaneously perform signal amplification and fault localization. The optical circulator directs both the forward optical signal and the reflected Rayleigh backscattering signal to appropriate ports, allowing the same hardware infrastructure to serve multiple purposes without requiring separate dedicated fault detection equipment.
2Difficulty of detecting and measuring
If optical time domain reflectometers are used for fault detection, then fault localization capability is improved, but device complexity increases
Solution Approach 1:
The optical circulator acts as an intermediary device that seamlessly integrates fault detection functionality into the existing amplifier infrastructure. It directs the forward optical signal to the amplifier input while routing the reflected Rayleigh backscattering signal to the power meter, enabling fault detection without requiring direct modification of the amplifier or addition of complex detection systems.
Solution Approach 2:
The patent replaces the complex mechanical OTDR system with a simpler optical-based solution using inherent Rayleigh backscattering. Instead of using external pulsed laser equipment and complex time-domain analysis, the system utilizes continuous optical signals and measures power levels of naturally occurring backscattered light, significantly simplifying the detection mechanism.
3Productivity
If additional optical time domain reflectometers are installed for each span, then automatic fault localization is achieved, but installation cost increases
Solution Approach 1:
Each optical amplifier is equipped with integrated fault detection capability through the addition of optical circulators and power meters, enabling automatic fault localization without requiring external monitoring equipment. The amplifiers themselves perform the monitoring function, eliminating the need for separate OTDR installations at each span.
Solution Approach 2:
The patent merges fault detection functionality with the existing optical amplifier infrastructure. By combining the amplifier, optical circulator, and power meter into an integrated monitoring system, the patent eliminates the need for separate OTDR equipment and reduces overall system complexity and installation costs.
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
Accurately determines fault locations at low cost, minimizing downtime and repair time by leveraging existing network components, and improving fault localization precision.
Implementation Method 1
detecting reflected signals generated by an optical signal travelling through the span
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention relates to a method for fault localization in an optical network, wherein the optical network includes at least one span, and wherein an optical signal travels through the at least one span, wherein each of the at least one span has associated amplifiers, wherein the associated amplifiers are connected to launch optical signals into a remainder of a corresponding optical transmission line, wherein the method (1) comprises the steps of: - for each span, respectively acquiring reflected signals generated by the optical signal travelling through the span by at least one power monitoring device (2); and - for each span, determining whether there is a fault in the corresponding span based on the corresponding acquired reflected signals, wherein, if there is a fault in the corresponding span, localization of the fault is determined based on the corresponding acquired reflected signals (3).