Optical Module Fiber Pinch Detection via Backscatter Monitoring
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Solution Overview
Problem
Conventional optical amplifier systems fail to detect fiber pinches, which can lead to safety hazards such as damage to equipment and injury, as they rely on signal interruption or pump back reflection, and are not effective in complex interconnection scenarios.
Innovation Solution
The method involves continuously monitoring the backscatter signal in an optical module, setting a threshold for detecting a fiber pinch based on double attenuation, and performing remedial actions such as reducing power or shutting off pumps, using an optical time domain reflectometer to ensure no fiber pinch is present, and integrating a photodetector to measure the backscatter signal produced by Rayleigh backscattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shutdown mechanisms rely on signal interruption or pump back reflection, then fiber cuts and open connectors can be detected, but fiber pinches cannot be detected
Solution Approach 1:
The patent introduces an optical service channel (OSC) as an intermediary signal path that is separate from the main signal path. By monitoring the OSC signal at the far end and comparing it with the transmitted OSC signal, the system can detect fiber pinches that affect the main signal path without being affected by pinches in the OSC path itself. This intermediary approach enables detection of fiber pinches that would otherwise be invisible to conventional back reflection or pump monitoring methods.
2Adaptability or versatility
If interconnection complexity increases, then more opportunities for fiber pinches near launch points arise, but conventional detection mechanisms remain unchanged
Solution Approach 1:
The OSC monitoring mechanism serves multiple functions: it enables detection of fiber pinches, provides a reference signal for comparison, and operates independently of the main signal path. This universal approach allows the same monitoring infrastructure to handle safety detection across varying system complexities and interconnection configurations, making the detection capability adaptable to different network topologies without requiring additional specialized mechanisms.
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
This solution effectively detects fiber pinches and initiates automatic remedial actions quickly, preventing damage and injury by monitoring backscatter signals and ensuring safe operation of high-powered optical amplifiers, particularly in Raman amplifiers and EDFAs, with rapid shutdown or power reduction capabilities.
Implementation Method 1
detecting the backscatter signal from the small portion of power, wherein the backscatter signal is a signal produced by Rayleigh backscattering (RBS) of the signal in the fiber
Data Source
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AI summary
A method, optical module, and optical amplifier are configured to detect fiber discontinuities at or near a port from which high powered optical signals are input into a fiber span. These fiber discontinuities can include fiber pinches, and are detected by monitoring for slight changes in a backscatter signal. Detection is quick and efficient based on the backscatter signal being attenuated by the fiber discontinuities twice, namely once as the high powered optical signals and again as the associated backscatter signal of the high powered optical signals returning to the port. A signal (84) may be amplified by a fibre amplifier (80) comprising an Erbium-doped fiber (86) and photodiodes (92,96). A fiber pinch (24) is detected by comparing the output power of the amplifier as measured by PD2 (96) and the backscattered Rayleigh light (94) resulting from an interaction of the residual pump light in the transport fiber (16) as detected by the back reflection monitor PD1 (92). In the case of a damage to the fiber (16) the ratio PD1/PD2 will decrease.