OTDR Module Correcting Optical Return Loss via Intrinsic Reflection Calibration
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Solution Overview
Problem
Existing methods for measuring Optical Return Loss (ORL) using Optical Time Domain Reflectometer (OTDR) modules are often inaccurate due to intrinsic reflections from the OTDR module itself, which interfere with the measurement of the fiber plant's ORL.
Innovation Solution
The OTDR module is calibrated by measuring intrinsic reflections using a test fiber wrapped around a mandrel, and the calibration information is used to correct the ORL measurements, separating the fiber plant's reflections from the module's internal reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ORL measurements are made using an OTDR module, then the measurement capability is extended, but the accuracy deteriorates due to intrinsic reflections from the OTDR module itself
Solution Approach 1:
The patent extracts and separates the intrinsic reflection component from the total measured reflection. By measuring the OTDR module's intrinsic reflection independently (using a high-reflection test object) and then subtracting it from the total reflection measurement, the patent isolates the true ORL of the fiber plant, thereby resolving the accuracy issue while maintaining measurement versatility
Solution Approach 2:
The patent introduces a high-reflection test object (such as an open connector or Fresnel reflector) as an intermediary calibration target. This intermediary allows the system to measure and characterize the OTDR module's intrinsic reflection properties, which then serve as a reference for correcting subsequent ORL measurements of actual fiber plants
2Length of stationary object
If the dynamic range is increased to measure weaker reflections, then the measurement range is extended, but the influence of internal reflections becomes more significant
Solution Approach 1:
The patent performs preliminary calibration by measuring the OTDR module's intrinsic reflection before conducting actual ORL measurements. This preliminary action characterizes the harmful internal reflections, allowing them to be compensated for in subsequent measurements. The calibration data is stored and applied as a correction factor, enabling accurate measurement of weak reflections without being overwhelmed by internal reflection artifacts
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 approach enhances the accuracy of ORL measurements by removing the influence of internal reflections, increasing the dynamic range from 30 dB to 45 dB and providing more robust and reliable ORL data.
Implementation Method 1
an ORL response is measured due to reflection of an ORL signal transmitted from the OTDR module along the fiber plant, and a peak OTDR response is measured due to reflection of an OTDR signal transmitted from the OTDR module along the fiber plant
Implementation Method 2
an ORL response is measured due to reflection of an ORL signal transmitted from the OTDR module along the fiber plant
Data Source
AI summary
An Optical Time Domain Reflectometer (OTDR) module obtains Optical Return Loss (ORL) of a fiber plant. Calibration information is obtained of at least internal OTDR reflections associated with the OTDR module. The OTDR module is connected to the fiber plant. An ORL response is measured due to reflections of an ORL signal transmitted from the OTDR module along the fiber plant, and a peak OTDR response is measured in response to reflections of an OTDR signal transmitted from the OTDR module along the fiber plant. A corrected ORL response of the fiber plant is determined by: using the measured peak OTDR response (e.g., peak value or area under the peak) and the calibration information to calculate the calculated ORL due to internal reflections, and then adjusting the measured ORL response by the calculated ORL to represent the corrected ORL of the fiber plant.