Optical Pulse Testing for Fiber Connection State Detection
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Solution Overview
Problem
Existing optical pulse test methods for detecting changes in the state of optical fiber connection portions, such as water immersion, require reference measurements and are affected by changes in gap intervals, making it difficult to determine the medium without prior information.
Innovation Solution
An optical pulse test apparatus and method using test optical pulses with broad spectral widths and varying center wavelengths to calculate reflection peak values, allowing for the determination of the medium at the connection portion without reference measurements and independent of gap interval changes, by averaging reflection peak values and transforming reflectance data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference measurements before immersion are used to determine water immersion, then the determination can be made, but the method requires prior reference information and comparison
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing reference values for different gap intervals (air gap and water immersion states) before actual measurement. When a measurement is taken, the system automatically compares the measured reflection peak value against these pre-stored references to determine the medium state, eliminating the need for manual before-after comparison procedures.
2Adaptability or versatility
If gap interval changes occur between measurements, then the connection portion geometry changes, but reference-based methods become invalid
Solution Approach 1:
The patent applies parameter changes by measuring the reflection peak value at multiple different wavelengths and observing how this parameter changes with wavelength. Since the reflection peak value's wavelength dependence differs between air and water immersion states, this method allows determination of the medium state without being affected by gap interval changes, as the wavelength-dependent pattern remains characteristic of each medium state.
3Ease of operation
If single wavelength measurement is used, then the measurement is simple, but the determination is affected by gap interval changes
Solution Approach 1:
The patent applies dimensionality change by extending the measurement from a single wavelength point to multiple wavelengths, adding the wavelength dimension to the measurement space. This transforms the problem from a one-dimensional measurement (single wavelength) to a two-dimensional measurement (wavelength vs. reflection peak value), allowing the system to distinguish between different medium states based on their unique wavelength-dependent patterns while remaining insensitive to gap interval variations.
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
Enables accurate determination of the medium at the optical fiber connection portion without prior reference data and is unaffected by changes in gap intervals, facilitating reliable identification of state changes.
Implementation Method 1
obtain distribution data (OTDR waveforms) based on intensities of a backscattered light of a Rayleigh scattered light originating from the test optical pulse propagating within the optical fiber
Implementation Method 2
a Fresnel reflected light
Implementation Method 3
measures power of longitudinal backscattered light while changing test wavelength of the OTDR, and plots the peak value of a reflection attenuation amount caused by Fresnel reflection generated in a gap of the connection portion as a function of wavelength
Data Source
AI summary
An object of the present invention is to provide an optical pulse test apparatus and an optical pulse test method that are capable of determining a change in state of an optical fiber connection portion without the need for reference and without being affected by changes in gap interval before and after the change in state. The optical pulse test apparatus according to the present invention is configured to perform an OTDR measurement by using test optical pulses having spectral widths of from several nm to several hundred nm arranged at intervals of several ten nm to several hundred nm, calculate a reflection peak value caused by the Fresnel reflection at the connection portion from the obtained OTDR waveform, and determine a state such as water immersion of the optical fiber connection portion based on the value.