Coded-Sequence OTDR Trace Correction Using Inter-Pulse Variation
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Solution Overview
Problem
Coded-sequence OTDR technologies generate artefacts in the OTDR trace due to unequal pulse amplitudes, especially in the presence of strong reflective events, compromising the characterization of individual events along the optical fiber.
Innovation Solution
Perform multiple coded-sequence OTDR acquisitions with different inter-pulse intervals to change the positions of artefacts in the OTDR traces, and combine these traces to reconstruct a high-quality OTDR trace by applying masks to eliminate artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If coded sequence OTDR acquisitions are performed with a single inter-pulse interval, then acquisition time is reduced through pulse compression, but artefacts are generated in the OTDR trace due to unequal pulse amplitudes
Solution Approach 1:
The invention segments the single OTDR acquisition into multiple coded sequence acquisitions, each performed with a different inter-pulse interval. By dividing the measurement into multiple segments with varying parameters, the artefacts generated in each individual acquisition are positioned differently in the trace, allowing them to be separated and eliminated through combination of the segmented results.
Solution Approach 2:
The invention changes the inter-pulse interval parameter across multiple coded sequence acquisitions. By varying this critical parameter, the position of artefacts in the OTDR trace changes between acquisitions, enabling the artefacts to be distinguished from actual fiber events and removed through mathematical combination of the multiple traces.
2Object-generated harmful factors
If multiple coded-sequence OTDR acquisitions with different inter-pulse intervals are performed and combined, then artefacts are eliminated from the OTDR trace, but acquisition time and processing complexity increase
Solution Approach 1:
The invention extracts and removes the harmful artefacts from the OTDR trace by performing multiple acquisitions with different inter-pulse intervals. The artefacts appear at different positions in each acquisition, allowing them to be identified and extracted from the combined trace through mathematical processing, leaving only the genuine fiber events.
Solution Approach 2:
The invention uses mathematical combination operations as an intermediary process to merge multiple OTDR traces acquired with different inter-pulse intervals. This intermediary processing step allows the system to eliminate artefacts while preserving genuine fiber events, transforming multiple imperfect traces into a single high-quality trace.
3Object-generated harmful factors
If multiple coded-sequence OTDR acquisitions with different inter-pulse intervals are performed and combined, then artefacts are eliminated from the OTDR trace, but acquisition time increases
Solution Approach 1:
The invention employs periodic coded sequence acquisitions with different inter-pulse intervals, where each acquisition cycle generates traces with artefacts at different positions. By performing a small number of periodic acquisitions and combining them through mathematical operations, the system eliminates artefacts while keeping the total acquisition time manageable.
Solution Approach 2:
The invention performs preliminary coded sequence acquisitions with different inter-pulse intervals to generate multiple traces before combining them. This preliminary action allows the artefacts to be positioned differently in each trace, facilitating their subsequent elimination through mathematical combination and resulting in a clean final trace.
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 method reduces and eliminates artefacts in the OTDR trace, providing improved characterization of optical fiber events without compromising trace quality.
Implementation Method 1
returning light, arising from backscattering and reflections along the fiber link, is detected and analyzed
Implementation Method 2
returning light, arising from backscattering and reflections along the fiber link, is detected and analyzed
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
There are provided coded-sequence OTDR methods and devices which diminish or erase artefacts created in the OTDR trace by performing multiple coded-sequence OTDR acquisitions with mutually different inter-pulse intervals so as to change the positions of the artefacts in the OTDR traces derived from these OTDR acquisitions and combining the multiple OTDR traces to reconstruct a reconstructed OTDR trace.