Optical Fiber Characteristic Measuring Device Using Parallel Frequency Analysis
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Solution Overview
Problem
The temporal gate method in optical fiber characteristics measurement apparatuses requires a significant measurement waiting time, leading to longer measurement times when characterizing optical fibers over a wide range, due to the need for pump pulse light to reciprocate and return before subsequent pulses can be incident, resulting in crosstalk and extended measurement durations.
Innovation Solution
The apparatus employs multiple frequency analyzers and a switch to selectively connect detectors at predetermined times based on the arrival of backscattered light, allowing for simultaneous measurement of multiple correlation peaks without waiting for the return of previous pulses, thereby reducing measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the temporal gate method is used to select correlation peaks by waiting for pump pulse light to reciprocate and return, then crosstalk between correlation peaks is avoided, but measurement time is significantly extended
Solution Approach 1:
The patent divides the measurement process into multiple parallel channels, each handling a different correlation peak. By using multiple frequency analyzers (first frequency analyzer for first correlation peak, second frequency analyzer for second correlation peak) and a switch to selectively connect them, the system processes multiple segments of the optical fiber simultaneously rather than sequentially, thereby reducing total measurement time while maintaining accuracy through dedicated analysis channels for each segment
Solution Approach 2:
The patent performs preliminary setup of multiple frequency analyzers and switching mechanisms before the actual measurement begins. The system pre-configures the temporal gate to selectively connect different frequency analyzers based on expected arrival times of backscattered light from different correlation peaks, allowing immediate parallel processing upon light incidence without sequential waiting periods
2Productivity
If multiple correlation peaks are measured simultaneously without waiting for pulse return, then measurement time is reduced, but crosstalk may occur between peaks
Solution Approach 1:
The patent introduces a switch as an intermediary component that selectively connects different frequency analyzers to the detector based on the arrival time of backscattered light from different correlation peaks. This intermediary mechanism enables simultaneous measurement of multiple peaks by routing signals from different time windows to appropriate analyzers, achieving both high speed and high accuracy through time-division multiplexing controlled by the switching element
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 approach significantly shortens the time required for measuring optical fiber characteristics by enabling the simultaneous selection and analysis of multiple correlation peaks, reducing the overall measurement duration to a fraction of that in traditional methods.
Implementation Method 1
receives interference between Brillouin scattered light emitted from one end of a measurement optical fiber and reference light
Implementation Method 2
receives interference between Brillouin scattered light emitted from one end of a measurement optical fiber and reference light (light frequency-modulated like pump light)
Data Source
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AI summary
An optical fiber characteristics measurement apparatus (1) includes: a light source (11) configured to output continuous light (L1) of which frequency is modulated; a first optical splitter (12) configured to split the continuous light into pump light (LP) and reference light (LR); a pulser (13) configured to pulse the pump light; a second optical splitter (14) configured to cause the pulsed pump light to be incident from one end of an optical fiber (FUT) and output backscattered light (LS) generated due to Brillouin scattering in the optical fiber; a detector (17) configured to detect interference light between the backscattered light and the reference light; a cutout unit (18, 20a, 34, 41, 42a) configured to cut out a detection signal output from the detector at predetermined time intervals; and a measurer (19, 35a, 35b) configured to measure characteristics of the optical fiber individually using the detection signal for each of the predetermined time intervals cut out by the cutout unit.