Optical Fiber Measurement Amplitude Modulation Cancellation
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Solution Overview
Problem
Optical fiber characteristics measurement apparatuses face challenges in improving measurement accuracy due to unintentional amplitude modulation of laser light during frequency modulation, which introduces noise and degrades measurement precision.
Innovation Solution
The apparatus includes a laser light source module with an optical amplifier that adjusts the amplitude of frequency-modulated laser light to cancel out unintentional amplitude modulation, ensuring only frequency modulation occurs, thereby enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency modulation is applied to laser light, then measurement capability is enabled, but amplitude modulation noise is introduced that degrades measurement accuracy
Solution Approach 1:
The patent converts the harmful amplitude modulation noise into a beneficial signal by generating a cancellation signal that mirrors the amplitude modulation characteristics. This cancellation signal is then combined with the frequency-modulated laser light to eliminate the amplitude modulation noise, thereby improving measurement accuracy while maintaining the frequency modulation capability.
Solution Approach 2:
The patent applies preliminary anti-action by generating and applying a cancellation signal before the measurement process to preemptively counteract the amplitude modulation noise. The cancellation signal is designed to have opposite phase characteristics to the expected amplitude modulation, thereby neutralizing its harmful effects before they can degrade the measurement accuracy.
2Measurement precision
If frequency-modulated laser light is used for measurement, then optical fiber characteristics can be measured, but unintentional amplitude modulation occurs as noise
Solution Approach 1:
The patent introduces an intermediary cancellation signal that acts as a mediator between the frequency-modulated laser light and the measurement process. This cancellation signal specifically targets and neutralizes the unintentional amplitude modulation without interfering with the frequency modulation, thereby improving Brillouin frequency shift measurement accuracy while preserving the essential measurement capability.
3Measurement precision
If amplitude modulation is present in frequency-modulated laser light, then noise is introduced, but removing amplitude modulation is difficult
Solution Approach 1:
The patent applies self-service by generating the cancellation signal from the same frequency modulation process that creates the amplitude modulation noise. The system uses its own internal characteristics to create the counteracting signal, eliminating the need for external complex filtering or modulation removal equipment. This approach reduces device complexity while effectively removing amplitude modulation to improve measurement accuracy.
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 configuration effectively cancels amplitude modulation, leading to improved measurement accuracy of optical fiber characteristics, particularly in Brillouin frequency shift measurements.
Implementation Method 1
an optical amplifier configured to adjust an amplitude of the frequency-modulated laser light outputted by the laser light source so as to cancel an amplitude modulation occurring in the frequency-modulated laser light outputted by the laser light source
Implementation Method 2
a laser light source driver configured to modulate a frequency of the laser light outputted by the laser light source
Implementation Method 3
The BOCDR optical fiber characteristics measurement apparatus can measure the temperature and strain at each position of an optical fiber by measuring the scattered light due to Brillouin scattering and measuring the Brillouin Frequency Shift (BFS)
Data Source
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AI summary
An optical fiber characteristics measurement apparatus (10) according to the present disclosure measures the characteristics of an optical fiber. The optical fiber characteristics measurement apparatus (10) includes a laser light source module (11) that outputs frequency-modulated laser light. The laser light source module (11) includes a laser light source (110) that outputs laser light, a laser light source driver (111) that modulates the frequency of the laser light outputted by the laser light source (110), and an optical amplifier (116) that adjusts the amplitude of the frequency-modulated laser light outputted by the laser light source (110) so as to cancel an amplitude modulation occurring in the frequency-modulated laser light outputted by the laser light source (110).