Fiber Measurement Device Waveform Equalization for High-Resolution Long-Distance Analysis
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Solution Overview
Problem
Current fiber measurement devices, such as OTDRs, face challenges in achieving high resolution for long distance fiber measurements due to non-linear optical phenomena and signal amplification issues, which deteriorate measurement resolution and limit the ability to accurately assess long distance fiber characteristics.
Innovation Solution
A fiber measurement device incorporating a band limiting circuit and a waveform equalizing circuit with differentiating and adding capabilities, allowing for high-resolution measurement of long distance fibers using high-power laser light and enabling real-time processing with simple analog circuits, while also switching between narrowband and wideband modes for different measurement requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal amplification is increased to improve detection sensitivity for long distance fiber measurements, then measurement capability for long distance fibers is improved, but measurement resolution deteriorates due to non-linear optical phenomena and signal distortion
Solution Approach 1:
The patent applies preliminary action by performing waveform equalization before signal analysis. The waveform equalizing circuit pre-compensates for distortion in the feedback light waveform using differentiating and adding circuits, ensuring that subsequent measurements are performed on already-corrected waveforms. This preliminary correction prevents distortion accumulation during signal amplification and processing, maintaining measurement resolution even for long distance fibers where significant signal attenuation occurs.
2Length of stationary object
If high-power laser light is used to improve signal strength for long distance measurements, then measurement range is extended, but measurement resolution deteriorates due to non-linear optical phenomena
Solution Approach 1:
The patent converts the harmful effect of non-linear optical phenomena into a beneficial measurement capability. By intentionally using high-power laser light that generates non-linear effects and then applying waveform equalization to correct the resulting distortion, the system achieves both extended measurement distance and maintained resolution. The waveform equalizing circuit effectively compensates for the distortion caused by high-power operation, allowing the system to operate in a regime that would otherwise be unusable.
3Measurement precision
If complex processing circuits are used to improve measurement resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex digital signal processing circuits with a simpler analog waveform equalizing circuit. The differentiating and adding circuits use basic analog components (capacitors, resistors, operational amplifiers) to perform waveform correction in the time domain, avoiding the need for complex digital processors. This substitution maintains measurement resolution while significantly reducing device complexity and enabling real-time processing.
4Measurement precision
If narrowband filtering is applied to improve signal-to-noise ratio, then measurement precision is improved, but frequency bandwidth is reduced
Solution Approach 1:
The patent addresses the bandwidth-resolution tradeoff by operating in the time domain rather than the frequency domain. Instead of using narrowband frequency filtering, the waveform equalizing circuit processes signals in the time domain using differentiation and addition operations. This dimensional change allows simultaneous preservation of both time-domain resolution and frequency bandwidth, as the equalization process does not require restricting the frequency spectrum.
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 device effectively measures long distance fiber characteristics with high resolution and wide frequency bandwidth, separating interfering signals and allowing for real-time, high-speed display of waveforms, without the need for complex processing circuits.
Implementation Method 1
The photodetector 106 detects laser light to generate a current by photoelectric conversion.
Implementation Method 2
a band limiting circuit adapted to extract, from a signal depending on the feedback light, a signal having a component corresponding to a frequency of the laser light
Implementation Method 3
a waveform equalizing circuit having a differentiating and adding circuit adapted to differentiate the first differentiation target signal to generate a first differentiation result signal and to add the first differentiation target signal and the first differentiation result signal
Data Source
AI summary
A fiber measurement device includes: a light detector adapted to detect feedback light of laser light output to a fiber; a band limiting circuit adapted to extract, from a signal depending on the feedback light, a signal having a component corresponding to a frequency of the laser light, wherein the signal extracted by the band limiting circuit is a first differentiation target signal; and a waveform equalizing circuit having a differentiating and adding circuit adapted to differentiate the first differentiation target signal to generate a first differentiation result signal and to add the first differentiation target signal and the first differentiation result signal.