Signal Light Interruption Detection Using Optical Interleaver
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Solution Overview
Problem
Conventional methods for detecting signal light interruption in fiber-optic communication systems, particularly those using wavelength-multiplexed light, face challenges in reliability due to complex configurations and unstable noise light components, making it difficult to accurately compare main signal light power with noise light power, especially when their levels are close.
Innovation Solution
The use of an optical interleaver to demultiplex wavelength-multiplexed light into separate frequency ranges for main signal and noise light components, allowing for reliable detection of signal light interruption by comparing power differences across these ranges, even when noise light power is high or unstable, without requiring a complicated configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable frequency filter is employed to detect signal light interruption at arbitrary wavelengths, then the detection capability across multiple wavelengths is improved, but the device complexity increases
Solution Approach 1:
The wavelength spectrum is segmented into two distinct frequency ranges (first and second ranges) using an optical interleaver. This segmentation allows simultaneous detection of multiple wavelength components without requiring a variable frequency filter, thereby maintaining multi-wavelength adaptability while simplifying the device configuration to use only fixed filters and photodetectors.
2Adaptability or versatility
If noise light components in wavelength bands other than the main signal light component are used for comparison, then the detection coverage is improved, but the measurement reliability deteriorates due to unstable noise light levels
Solution Approach 1:
The main signal light component is extracted from the composite light signal by using the optical interleaver to separate it into the first frequency range, while noise light components are directed to the second frequency range. This extraction allows reliable detection by comparing the main signal component against a stable reference (the sum of both ranges) rather than comparing against unstable narrowband noise components.
3Measurement precision
If the main signal light component level is just slightly higher than the noise light component level, then the signal-to-noise ratio is improved, but the detection reliability deteriorates due to difficulty in distinguishing signal from noise
Solution Approach 1:
The detection method merges the main signal light component (first frequency range) with the noise light components (second frequency range) into a composite reference signal. By comparing the main signal component against this combined reference, the system maintains detection reliability even when the signal-to-noise ratio is low, as the comparison is based on total power differences rather than attempting to distinguish individual components.
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 high-reliability and high-speed detection of signal light interruption in wavelength-multiplexed systems, reducing component count and costs, and maintaining a significant power difference between main signal and noise light components, thus improving detection accuracy.
Implementation Method 1
wavelength division multiplexing for increasing the number of signal lights that can be communicated through one optical fiber (the number of signal lights differing in the wavelength band)
Implementation Method 2
a first photodetector to detect first light power of the light in the first frequency ranges and output a first signal corresponding to the first light power
Data Source
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AI summary
A signal light interruption detection device (35) includes an optical interleaver (352) that demultiplexes wavelength-multiplexed light into light in first frequency ranges corresponding to a first frequency grid including frequencies at regular frequency intervals in which a main signal light component can be arranged and light in second frequency ranges corresponding to a second frequency grid shifted from the first frequency grid by a half cycle of the regular frequency intervals, a first optical detector (353) that detects first light power as total power of the light in the first frequency ranges, a second optical detector (354) that detects second light power as total power of the light in the second frequency ranges, and a judgment unit (355) that outputs a notification signal based on a difference between the first light power detected by the first optical detector (353) and the second light power detected by the second optical detector (354).