Optical Communication System Supervisory Signal Extraction
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Solution Overview
Problem
In long-distance optical communication systems, such as submarine cable systems, the modulation degree of supervisory signals decreases as additional optical signals are introduced, making it difficult for repeaters to extract and receive these signals, and supervision may be lost if only add-on optical signals are transmitted without a superimposed supervisory signal.
Innovation Solution
An optical communication system that includes a low-rate-signal extraction unit to convert supervisory signals from existing optical signals into electric signals, which are then superimposed onto additional optical signals using a second low-rate-signal superimposition unit, ensuring the repeater can maintain supervision without reducing the modulation degree of the low-rate supervisory signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional optical signals are introduced to increase transmission capacity, then the transmission capacity is improved, but the modulation degree of supervisory signals decreases
Solution Approach 1:
The patent segments the optical signal transmission into multiple independent wavelength channels. Each channel can carry data signals independently, while the supervisory signal is extracted and re-superimposed on selected channels to maintain adequate modulation degree. This segmentation allows the system to handle multiple add-on optical signals while preserving supervisory signal quality on specific wavelengths.
2Productivity
If multiple add-on optical signals are transmitted without superimposing supervisory signals, then the transmission capacity is improved, but the repeater cannot extract and receive supervisory signals
Solution Approach 1:
The patent applies preliminary action by extracting the supervisory signal from the incoming optical signal before the repeater amplifies and retransmits it. The extracted supervisory signal is then re-superimposed on the outgoing optical signal at an appropriate level, ensuring that the repeater can detect and process the supervisory signal while handling multiple add-on data channels.
3Adaptability or versatility
If the supervisory signal is superimposed on intensity modulation of optical signals, then the supervisory signal can be transmitted, but the modulation degree decreases when multiple optical signals are multiplexed
Solution Approach 1:
The patent applies local quality by selectively applying supervisory signal superimposition to specific wavelength channels based on their characteristics and requirements. Not all optical channels have the supervisory signal re-superimposed with the same strength; instead, the system adjusts the supervisory signal level locally for each channel or group of channels to maintain adequate modulation degree while accommodating multiple add-on signals.
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 system effectively maintains supervision by the repeater even when additional optical signals are introduced, without degrading the modulation degree of the low-rate supervisory signal, and allows for increased transmission capacity by utilizing high-frequency optical signals.
Implementation Method 1
a low-rate-signal superimposition unit that superimposes a low-rate signal on an optical signal by intensity modulation
Implementation Method 2
the optical repeater amplifies and repeats a high-rate main signal in a state of light without the signal being regenerated
Data Source
AI summary
An optical communication system includes an optical-signal transmission unit transmitting an existing optical signal and a low-rate-signal superimposition unit superimposing a low-rate signal on the existing optical signal by intensity modulation. It further includes: a low-rate-signal extraction unit that extracts the low-rate signal from the existing optical signal on which the low-rate signal is superimposed and converts the extracted low-rate signal into a low-rate electric signal; an add-on optical-signal transmission unit that transmits an add-on optical signal; a low-rate-signal superimposition unit that superimposes a low-rate signal on the add-on optical signal by the intensity modulation based on the low-rate electric signal; and a repeater that repeats the add-on optical signal on which the low-rate signal is superimposed, to a transmission destination.