Optical Transmitter Receiver Digital Polarization Scrambling
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Solution Overview
Problem
Polarization-dependent fluctuations in optical communication systems, such as PMD, PDL, and PDG, cause degradation in communication quality, and existing technologies struggle to effectively suppress these fluctuations, especially at high speeds, and are burdensome in terms of device size and cost.
Innovation Solution
An optical transmission/reception system that includes a modulator and a transmission-side signal processor performing digital signal processing to impart a polarization change to the signal light, and a reception-side processor that applies a substantially inverse polarization change, using digital signal processing to manage polarization scrambling and pre-equalization, allowing for high-speed polarization control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If optical polarization scrambling is performed collectively for all channels in a relay node, then device size and cost are reduced, but channel-specific polarization penalties increase depending on modulation methods
Solution Approach 1:
The patent replaces optical polarization scrambling devices with digital signal processing techniques. The transmission-side signal processor applies digital polarization scrambling to the signal light, and the reception-side signal processor applies inverse polarization scrambling to compensate. This substitution eliminates the need for bulky optical polarization scramblers in relay nodes while maintaining channel-specific performance optimization through software-controlled processing.
Solution Approach 2:
The patent dynamically adjusts polarization scrambling parameters through digital signal processing. The transmission-side processor applies polarization scrambling with specific parameters, and the reception-side processor applies inverse scrambling with corresponding parameters. This allows flexible, channel-specific polarization control without physical device reconfiguration, resolving the contradiction between device simplicity and channel performance optimization.
2Reliability
If adaptive polarization separation signal processing is used to respond to polarization fluctuations, then communication quality improves, but the system cannot respond to high-speed polarization changes
Solution Approach 1:
The patent replaces conventional adaptive polarization separation processing with a digital signal processing approach that applies polarization scrambling at high speeds. The transmission-side signal processor implements polarization scrambling through digital operations, enabling response to high-speed polarization changes while maintaining communication quality through coordinated inverse processing at the reception side.
3Manufacturing precision
If pre-equalization is performed on the transmission side to suppress signal degradation, then waveform distortion is reduced, but the influence of constantly fluctuating polarization properties cannot be suppressed
Solution Approach 1:
The patent applies preliminary polarization scrambling at the transmission side through the transmission-side signal processor. This pre-processing action compensates for upcoming polarization fluctuations by applying the opposite polarization change before transmission. The reception-side signal processor then applies inverse scrambling to restore the original signal, effectively suppressing the influence of constantly fluctuating polarization properties while maintaining waveform quality.
Data Source
AI summary
An optical transmission/reception system includes a modulator for modulating light based on data to output signal light; a transmission-side signal processor performing transmission-side digital signal processing which imparts a polarization change to the signal light by the optical modulation with respect to an input signal; an optical transmitter in which the modulator performs the optical modulation based on the input signal subjected to the transmission-side digital signal processing in the transmission-side signal processor; and an optical receiver including a converter converting the signal light inputted from the optical transmitter via a transmission path to a digital electric signal for each polarization component, and a reception-side signal processor performing reception-side digital signal processing which imparts a polarization change having a property substantially inverse to a property of the polarization change in the transmission-side signal processor with respect to the digital electric signal from the converter.