Optical Fiber Measurement Using Dual-Wavelength Raman Offset
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Solution Overview
Problem
Conventional optical fiber measurement methods are inaccurate due to stimulated Raman scattering effects, which transfer power between light rays of different wavelengths, affecting the accuracy of measurement results.
Innovation Solution
An optical fiber measurement system using a signal generator, a first optical time-domain reflectometer, and a wavelength division multiplexer to send measurement light rays with wavelengths longer and shorter than the signal light ray, allowing power transfer to be offset, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional optical fiber measurement method is used, then the measurement process is simple, but the measurement accuracy deteriorates due to stimulated Raman scattering effects causing power transfer between light rays of different wavelengths
Solution Approach 1:
The measurement process is segmented into multiple independent measurement channels, each using light rays of specific wavelengths. By segmenting the measurement into separate wavelength-based measurements, the system can isolate and eliminate the harmful stimulated Raman scattering effects while maintaining overall measurement accuracy.
Solution Approach 2:
A wavelength division multiplexer is introduced as an intermediary device to combine multiple measurement light rays of different wavelengths without allowing them to interact through stimulated Raman scattering. This intermediary enables the system to measure multiple parameters simultaneously while preventing the harmful power transfer between different wavelength light rays.
2Ease of operation
If measurement light rays of different wavelengths are transmitted in the optical fiber, then the measurement process can be simplified, but harmful stimulated scattering effects occur causing power transfer and measurement inaccuracy
Solution Approach 1:
The patent exploits the stimulated Raman scattering effect in a controlled manner by using wavelength division multiplexing. The harmful power transfer effect is converted into a beneficial measurement capability by measuring the scattering characteristics themselves, which provide information about the optical fiber's transmission properties while eliminating the interference in the measurement process.
Solution Approach 2:
The wavelength division multiplexer serves as an intermediary that allows multiple wavelength light rays to coexist in the optical fiber without interacting through stimulated Raman scattering. This intermediary device enables simplified measurement operations while preventing harmful scattering effects from affecting the measurement accuracy.
3Measurement precision
If a single measurement light ray is used, then the system complexity is low, but the measurement accuracy is insufficient due to inability to offset power transfer effects
Solution Approach 1:
Multiple measurement light rays of different wavelengths are merged into a single combined light ray using a wavelength division multiplexer. This merging allows the system to maintain low complexity while improving measurement accuracy by incorporating multiple wavelength measurements that can offset each other's power transfer effects.
Solution Approach 2:
The combined light ray serves multiple functions simultaneously: it acts as a measurement signal for characterizing optical fiber transmission properties, while also serving as a reference to offset the power transfer effects of stimulated Raman scattering. This multi-functionality improves measurement accuracy without proportionally increasing system complexity.
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 system effectively eliminates interference from stimulated scattering effects, enhancing the accuracy of optical fiber measurements without impacting normal service transmission.
Implementation Method 1
The wavelength division multiplexer is configured to: combine the first measurement light ray, the second measurement light ray, and the signal light ray, send a combined light ray to an optical fiber
Implementation Method 2
when light rays of different wavelengths are transmitted in an optical fiber, a stimulated Raman scattering effect occurs. Specifically, power of a short-wavelength light ray is transferred to a long-wavelength light ray
Implementation Method 3
The first optical time-domain reflectometer is configured to send a first measurement light ray and a second measurement light ray whose wavelengths are respectively longer than and shorter than a wavelength of the signal light ray to the wavelength division multiplexer
Data Source
AI summary
An optical fiber measurement system includes an optical time-domain reflectometer, a wavelength division multiplexer, and a signal generator. The signal generator sends a signal light ray to the wavelength division multiplexer. The optical time-domain reflectometer sends two measurement light rays whose wavelengths are respectively longer than and shorter than a wavelength of the signal light ray to the wavelength division multiplexer. The wavelength division multiplexer combines the two measurement light rays and the signal light ray, sends a combined light ray to an optical fiber, and sends a light ray returned by the optical fiber to the optical time-domain reflectometer, so that the optical time-domain reflectometer determines performance of the optical fiber based on the returned light ray.