Fiber Fuse Detection via Reverse Light Monitoring
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Solution Overview
Problem
Existing methods for preventing the progression of fiber fuse in optical fibers are inadequate, as they either fail to stop the fiber fuse phenomenon beyond the termination point or cause adverse effects on signal transmission characteristics due to large differences in core diameters.
Innovation Solution
A fiber fuse detecting apparatus that uses reverse direction propagation light to detect changes in output levels, employing an optical coupler and electric filters to extract specific frequency bands, and a warning system to stop or reduce laser power when a fiber fuse is detected, thereby preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical fiber with enlarged core diameter is inserted midway to prevent fiber fuse progression, then the fiber fuse phenomenon can be stopped in that portion, but the progress of fiber fuse beyond the termination point cannot be stopped and mode conversion occurs affecting signal transmission characteristics
Solution Approach 1:
The patent replaces the mechanical/optical structure modification approach (enlarged core fiber insertion) with an optical detection and control system. The system uses a detection apparatus to monitor for fiber fuse events and a control system to shut down the light source, eliminating the need for physical fiber modifications that cause mode conversion while still achieving fiber fuse prevention.
Solution Approach 2:
The patent implements a feedback control system where the detection apparatus continuously monitors the optical fiber for fiber fuse events, and when detected, triggers a shutdown signal to the light source. This closed-loop feedback mechanism enables dynamic prevention of fiber fuse progression without requiring permanent structural modifications to the fiber that would cause harmful mode conversion.
2Productivity
If high power light is propagated in optical fiber to extend non-repeater distance and increase multiplex numbers, then communication capacity and transmission distance are improved, but the risk of fiber fuse phenomenon increases due to higher optical power density
Solution Approach 1:
The patent implements preliminary detection capabilities that monitor for early signs of fiber fuse events before they can cause catastrophic damage. By detecting the periodic signals generated by developing fiber fuse phenomena at their inception, the system can trigger preventive shutdowns, allowing high power transmission to continue safely while preventing fuse events from progressing.
Solution Approach 2:
The detection apparatus provides continuous feedback monitoring of the optical fiber system, enabling real-time detection of fiber fuse events. This feedback mechanism allows the system to maintain high power operation for improved communication capacity while immediately responding to and preventing fiber fuse progression through automated light source shutdown.
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
The apparatus effectively detects fiber fuse and suppresses its progression, preventing damage to the optical fiber by quickly stopping or reducing the laser power, thus avoiding burn damage and maintaining signal transmission quality.
Implementation Method 1
light receiving means that photo-electrically converts light input by the light input means
Data Source
AI summary
A fiber fuse detecting apparatus provides early detection of a fiber fuse generation in an optical fiber that propagates laser light, preventing the damage from expanding. It comprises light input means arranged on a laser light incidence side of the optical fiber that inputs at least a portion of reverse direction propagation light propagating in a reverse direction to light incidenting the optical fiber, light receiving means that photo-electrically converts light input by the light input means, electric filter means that extracts from an output signal of the light receiving means a prescribed frequency band component that contains a periodic signal due to fiber fuse, detecting means that detects change of or a prescribed value in output level of the electric filter means, and warning means that emits a warning signal in response to a detection output of the detecting means. The laser light to the optical fiber is stopped or reduced by means of the warning means.