In-Service Fiberoptic Breakage Location via Frequency Sweeping
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Solution Overview
Problem
Existing fiberoptic network monitoring systems fail to accurately locate fiber breakage points without disrupting normal operation and require trained personnel to interpret complex data, making it difficult to maintain network integrity and performance.
Innovation Solution
An in-service monitoring system that uses an out-of-band optical test signal modulated at a periodically swept or ramped frequency to determine the distance to a breakage point by comparing the modulation frequency offset and magnitude of the returning signal, allowing for fault detection in fiberoptic links without interfering with data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Optical Time-Domain Reflectometry (OTDR) is used to locate fiber breakage, then the distance to breakage point can be determined, but normal operation of the fiberoptic link is disturbed and output data are complex requiring trained personnel to interpret
Solution Approach 1:
The patent changes the monitoring parameter from time-domain reflectometry to frequency-domain optical test signals with periodic frequency sweeping. This transforms the complex time-domain OTDR data into simpler frequency-domain measurements that can be automatically interpreted by processing the frequency offset and magnitude of reflected test signals, eliminating the need for trained personnel while maintaining breakage location capability
Solution Approach 2:
The patent replaces the mechanical/optical time-domain measurement system with an electrical frequency-domain measurement system. By modulating optical test signals at periodically sweeping frequencies and measuring frequency offsets in the reflected signals, the system substitutes complex optical time-domain data collection with simpler electrical frequency measurements that are easier to process and interpret
2Measurement precision
If powerful laser pulse is launched for OTDR measurement, then distance to fiber breakage can be determined, but optical data transmission is interfered with
Solution Approach 1:
The patent employs periodic frequency sweeping of optical test signals rather than continuous powerful laser pulses. The test signal frequency is periodically varied in a controlled manner, allowing measurements to be taken during specific time windows without continuously interfering with data transmission. This periodic action enables breakage detection while maintaining normal network operation during non-measurement intervals
Solution Approach 2:
The patent introduces an intermediary frequency modulation layer between the optical test signal and the fiber medium. By modulating the optical signal at sweeping frequencies and using frequency offset detection as an intermediary measurement method, the system avoids direct interference with the fiber's data transmission capability while still achieving accurate breakage location through the frequency-domain analysis of reflected signals
3Reliability
If in-service monitoring is implemented without frequency sweeping, then normal operation is maintained, but precise location of fiber breakage cannot be achieved
Solution Approach 1:
The patent implements periodic frequency sweeping of optical test signals during normal network operation. The frequency sweeping occurs in controlled cycles that do not continuously disrupt service, allowing the system to maintain reliability while achieving precise breakage location through frequency-domain analysis. The periodic nature enables measurements to be taken during low-traffic periods or in a manner that minimizes operational impact
Solution Approach 2:
The patent changes the test signal parameter from static frequency to periodically sweeping frequency. This parameter change enables the system to distinguish between different breakage locations by measuring frequency offsets, achieving precise location capability while the periodic nature of the sweeping allows the system to operate in-service without permanently disrupting normal network function
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 precise location of fiber breaks and deterioration detection within fiberoptic networks, reducing the need for trained personnel and minimizing operational disruption, while providing effective monitoring of multiple links.
Implementation Method 1
One known method of determining a distance to a fiber breakage is Optical Time-Domain Reflectometry (OTDR). In OTDR, a powerful laser pulse is launched at a proximal end of a fiberoptic link, and a time dependence of the reflected light power is monitored.
Implementation Method 2
an out-of-band optical test signal modulated at a modulation frequency that is periodically swept or ramped in time
Data Source
AI summary
An optical fiber breakage point may be located by coupling to the optical fiber an out-of-band optical test signal modulated at a periodic modulation pattern. A distance to the breakage point may be determined from a difference between modulation patterns of transmitted and received test signals.