Digital Optical Coherent Transmission Amplitude Skew Control
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Solution Overview
Problem
High-speed signal transmission in optical communication systems faces issues such as reduced optical signal-to-noise ratio, insufficient wavelength bandwidth, and waveform distortion due to amplitude variance and skew between channels, which degrade signal quality.
Innovation Solution
A digital optical coherent transmission device with an O/E converter, analog/digital conversion unit, and amplitude/skew control units that utilize constellation information to adjust signal amplitudes and compensate for skew, ensuring optimal signal processing and demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If signal transmission speed is increased to achieve higher data rates, then productivity is improved, but signal quality deteriorates due to reduced OSNR tolerance and waveform distortion
Solution Approach 1:
The patent applies parameter changes by adjusting the amplitude of electric signals through amplitude control units based on constellation information. This compensates for amplitude variance caused by high-speed transmission, maintaining signal quality despite increased transmission speed and waveform distortion
Solution Approach 2:
The patent implements feedback mechanisms where constellation information is acquired from the received signal and used to control the amplitude adjustment. This closed-loop feedback system continuously compensates for signal degradation, enabling high-speed transmission while maintaining reliability
2Reliability
If amplitude control is applied to correct signal variance, then signal quality is improved, but device complexity increases due to additional control units
Solution Approach 1:
The amplitude control units are integrated within the existing O/E converter structure, allowing the same hardware components to perform both optical-to-electrical conversion and amplitude control functions. This multi-functionality reduces overall device complexity while maintaining signal quality improvement
Solution Approach 2:
The system uses its own received signal to generate constellation information, which then automatically controls the amplitude adjustment without requiring external intervention. This self-service mechanism simplifies the control architecture while effectively correcting signal variance
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
Improves signal quality by correcting amplitude variance and skew, enhancing the tolerance against waveform distortion and noise, thereby maintaining high transmission performance in multivalued modulation and frequency division multiplexing systems.
Implementation Method 1
an O/E converter 25 that optical-coherent-receives a received optical signal and converts the optical signal into an electric signal
Data Source
AI summary
An optical signal is converted into an electric signal by an O/E converter on the reception side, and converted into a digital signal by an analog/digital conversion unit. In a capture unit A at the input stage of the digital signal processing unit at the next stage, the constellation of a signal output from an analog/digital conversion unit is acquired for each polarization. According to the constellation information, the amplitude value of the electric signal input to the analog/digital conversion unit is corrected so that the value is optimum. Also, the capture unit B acquires the constellation on the signal after the demodulation by the digital signal processing. According to the constellation information, the amplitude of the I and Q signals and the skew between the I and Q signals are corrected.