Optical Pulse Test Device Multi-Pulse Width Integration
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Solution Overview
Problem
Existing OTDR waveform measurement techniques face challenges in detecting adjacent events due to trade-offs between dynamic range and SN ratio, leading to difficulties in detecting events on the far end or small loss differences, which are often buried in noise.
Innovation Solution
An optical pulse test device and method that determine pulse widths based on cumulative loss for each event in the OTDR waveform, integrating analysis results to secure a required SN ratio, using OTDR waveform measurement, event analysis, and analysis result integration units to calculate and position events, and perform least square approximation or nonlinear fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pulse width is increased to secure dynamic range and SN ratio, then dynamic range and SN ratio are improved, but distance resolution deteriorates and adjacent events cannot be detected
Solution Approach 1:
The patent segments the measurement process by measuring OTDR waveforms with multiple different pulse widths and then integrating the analysis results. This allows the system to capture both far-end events (requiring large pulse widths for SN ratio) and adjacent events (requiring small pulse widths for distance resolution) without compromise.
Solution Approach 2:
The patent changes the pulse width parameter dynamically by measuring with multiple pulse widths and selecting/appropriately weighting results based on the cumulative loss calculation. This allows optimization of both SN ratio and distance resolution depending on the specific measurement requirements and event characteristics.
2Measurement precision
If pulse width is reduced to secure distance resolution, then distance resolution is improved, but dynamic range is reduced and far-end events cannot be detected
Solution Approach 1:
The patent segments the measurement approach by using multiple pulse widths - small pulse widths for near-end events requiring high distance resolution, and large pulse widths for far-end events requiring high dynamic range. The integration unit then combines these segmented measurements into a comprehensive result.
Solution Approach 2:
The patent adds a new dimension to the measurement approach by measuring with multiple pulse widths simultaneously and integrating results. This multi-dimensional approach allows the system to overcome the limitations of single-pulse-width measurements and detect events across the entire fiber length with both high resolution and high dynamic range.
3Reliability
If pulse width is increased to detect far-end events, then dynamic range is improved, but adjacent events become undetectable due to reduced distance resolution
Solution Approach 1:
The patent segments the detection task by measuring with multiple pulse widths and integrating results. Small pulse widths enable detection of adjacent events with high resolution, while large pulse widths ensure detection of far-end events with high dynamic range. The integration process combines these segmented detection results into a complete event list.
4Measurement precision
If pulse width is reduced to detect adjacent events, then distance resolution is improved, but SN ratio deteriorates and small loss events are buried in noise
Solution Approach 1:
The patent segments the measurement process into multiple measurements with different pulse widths. Small pulse widths provide high distance resolution for adjacent event detection, while large pulse widths provide high SN ratio for detecting small loss events. The integration unit combines these segmented results to overcome the limitations of individual measurements.
Data Source
AI summary
According to the present disclosure, an optical pulse test device includes an OTDR waveform measurement unit that measures an OTDR waveform with a plurality of pulse widths, an event analysis unit that calculates a level, a loss, and a return loss at a start point of each event, and an analysis result integration unit that calculates a cumulative loss at the start point and an end point of each event from the level, the loss, and the return loss at the start point of each event, determines a pulse width that enables securing of a required SN ratio or more for each of the start point and the end point of each event, integrates the cumulative loss at each of the start point and the end point of each event with the determined pulse width, and sets the integrated cumulative loss as an analysis result.