Optical Power Loss Measurement Reference Correction
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Solution Overview
Problem
Existing optical power loss measurement (OPLM) techniques, such as those used in optical loss test sets (OLTSs), face limitations in accurately measuring insertion loss values, particularly when using fiber-pigtailed detectors, which introduce biases and are not applicable for all scenarios, especially in modern short optical fiber link applications where connector losses dominate the measurement uncertainty.
Innovation Solution
A method involving two OPLM devices with patch cords, where a corrected reference power value is determined by measuring power values at both ends of reference optical waveguides and using a large-area detector to account for connector losses, allowing for accurate insertion loss measurement similar to the one-test cord procedure while enabling other measurements like bi-directional loss and optical return loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the one-cord reference procedure is used, then measurement accuracy is improved, but the device complexity increases and other measurement types cannot be performed
Solution Approach 1:
The patent segments the reference measurement process into two separate cord connections: a first cord connecting the light source to the DUT, and a second cord connecting the DUT to the power meter. This segmentation allows the system to perform accurate insertion loss measurements while maintaining the ability to perform other measurement types by independently configuring each cord connection.
Solution Approach 2:
The patent introduces a reference optical waveguide as an intermediary element that is optically coupled to both the light source and the power meter. This reference waveguide serves as a mediator to establish a reference power level that accounts for connector losses, enabling accurate measurements while preserving measurement versatility.
2Ease of operation
If fiber-pigtailed detectors are used, then ease of operation is improved, but measurement precision deteriorates due to bias introduction
Solution Approach 1:
The reference optical waveguide acts as an intermediary that compensates for the bias introduced by fiber-pigtailed detectors. By measuring the reference power level through this waveguide and using it to correct the insertion loss calculation, the system maintains ease of operation with pigtailed detectors while restoring measurement precision.
Solution Approach 2:
The patent replaces the direct mechanical connection approach (where the detector directly measures the signal) with an optical substitution approach. Instead of relying on the detector's direct measurement, the system uses optical reference waveguides to establish a reference level, substituting the mechanical measurement path with an optical reference path that eliminates detector-induced bias.
3Adaptability or versatility
If the two-cord or three-cord reference procedure is used, then adaptability is improved, but measurement precision deteriorates due to connector loss bias
Solution Approach 1:
The reference optical waveguide serves as a mediator that specifically addresses the connector loss bias problem. By introducing this intermediary element that is optically coupled to both the light source and power meter, the system can perform versatile measurements while accurately accounting for connector losses through the reference measurement, thereby maintaining measurement precision.
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 method provides accurate insertion loss measurements with reduced uncertainty, comparable to the one-test cord procedure, while allowing for other types of measurements, and corrects for biases introduced by fiber-pigtailed detectors, ensuring reliable results even in low-loss DUTs.
Implementation Method 1
measuring a reference power value of the OPLM system resulting from the propagation of light from the optical source to the detector
Implementation Method 2
measuring a first power value of all test light outputted from a first reference optical waveguide; measuring a second power value of all said test light outputted from a reference waveguide link
Data Source
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AI summary
There is provided a method which allows for measuring, using an optical power loss measurement system (e.g., two optical loss test set units and associated patch cords), the insertion loss value of a DUT with a degree of accuracy similar to what can be provided using the one-test cord procedure while maintaining the convenience associated with the two-cord and the three-cord reference procedures, notably allowing other types of measurement to be performed on the DUT.