Multimode Fiber Selection via Radial Offset Delay Slope
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for assessing the Effective Modal Bandwidth (EMB) of multimode optical fibers are limited to a single wavelength, making it costly and time-consuming to ensure high modal bandwidth over a wide wavelength range, such as between 850 nm and 950 nm, which is essential for next-generation high-speed data communications.
Innovation Solution
A method that uses DMD plots and radial offset delay (ROD) slope analysis at a single wavelength to select wide-band multimode fibers by applying linear fits to specific radial offset ranges and comparing slope parameters to predetermined criteria, allowing for the prediction of EMB across a broader wavelength spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EMB assessment is performed at multiple wavelengths to ensure high modal bandwidth over wide wavelength range, then reliability of wide-band performance is improved, but measurement time and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by performing DMD measurement at a single reference wavelength (850 nm) to obtain ROD slope parameters before actual wide-band operation. These pre-measured parameters are then used to predict EMB performance across the entire wavelength range (850-950 nm), eliminating the need for time-consuming multi-wavelength measurements while ensuring reliable wide-band performance assessment
Solution Approach 2:
The patent uses copying by creating a predictive model based on DMD measurement data at one wavelength. The ROD slope parameters obtained from the reference measurement serve as a copy or proxy that accurately represents the fiber's modal bandwidth characteristics across the entire wide-band wavelength range, allowing virtual assessment without physical re-measurement at each wavelength
2Reliability
If EMB assessment is performed at multiple wavelengths to ensure high modal bandwidth over wide wavelength range, then reliability of wide-band performance is improved, but measurement cost increases significantly
Solution Approach 1:
The patent performs the expensive DMD measurement activity only once at a reference wavelength as a preliminary step. The resulting ROD slope parameters are then reused for predicting performance across all wavelengths, eliminating the need for repeated costly measurements and significantly reducing overall measurement cost while maintaining reliability
Solution Approach 2:
The patent achieves universality by making the single DMD measurement at 850 nm serve multiple functions: it characterizes the fiber's modal dispersion properties, provides ROD slope parameters for EMB prediction, and validates wide-band performance across the entire 850-950 nm range. One measurement thus performs the work of multiple wavelength-specific assessments
3Ease of operation
If traditional single wavelength EMB assessment is used, then measurement simplicity is maintained, but accuracy of wide-band performance prediction deteriorates
Solution Approach 1:
The patent transforms the traditional EMB assessment approach by changing the key parameter from direct EMB measurement at each wavelength to ROD slope parameter extraction from DMD data. This parameter transformation allows a single measurement at one wavelength to provide accurate predictions across the wide-band range, maintaining simplicity while improving precision
Solution Approach 2:
The patent substitutes the mechanical approach of physically measuring EMB at multiple wavelengths with a computational method. By using mathematical modeling and ROD slope analysis on DMD data from a single wavelength measurement, the system replaces repeated physical measurements with computational prediction, maintaining operational simplicity while achieving accurate wide-band performance assessment
Data Source
Figure 1~2
Figure 3
Figure 4~9
AI summary
The invention relates to a method for selecting wide-band multimode optical fibers from a single wavelength, the method comprising the following steps of, for each multimode optical fiber: obtaining (300) a first DMD plot using a measurement of DMD carried out at a first single wavelength, obtaining (310), from the first DMD plot, a first multimode fiber specification parameter; and for each fiber: obtaining (320), from the first DMD plot, a curve representative of a radial offset delay, called ROD curve, as a function of the radial offset value; applying (330) a linear fit on the ROD curve for at least two radial offset value ranges; obtaining (340) from the linear fit and for each radial offset value range, an average radial offset delay slope, called ROD slope; selecting (350) the multimode optical fibers meeting a first predetermined specification criterion for the first multimode fiber performance parameter, and for which the at least two computed ROD slopes meet a predetermined slope criterion.