Mode-Multiplexed Optical Transmission System Signal Separation
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Solution Overview
Problem
In mode-multiplexed optical transmission systems using multi-mode or few-mode fibers, high-order spatial modes are more susceptible to power loss and gain variations, leading to significant transmission characteristic deviations and reduced transmission capacity and distance due to mode-dependent loss.
Innovation Solution
An optical transmission system that includes transmitters, optical splitters or switches, a multiplexer, a mode-multiplexed fiber, a demultiplexer, and receivers, with a signal detector for digital signal processing to separate and extract data sequences from mode-multiplexed signals, effectively reducing information errors by improving signal separation and transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mode-multiplexed optical transmission is used to increase transmission capacity, then transmission capacity is improved, but transmission characteristic deviation increases due to mode-dependent loss
Solution Approach 1:
The patent applies local quality by treating different spatial modes differently through mode-specific digital signal processing. Each spatial mode receives customized equalization and compensation parameters tailored to its specific loss characteristics, allowing high-order modes with poor transmission characteristics to be individually managed rather than uniformly treated, thus resolving the contradiction between increasing transmission capacity and maintaining transmission characteristic reliability
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting digital signal processing parameters for each spatial mode based on its transmission characteristics. The system changes equalization coefficients, compensation parameters, and processing algorithms according to the specific loss profile of each mode, enabling the system to maintain reliability across all modes while maximizing overall transmission capacity
2Productivity
If high-order spatial modes are used to increase transmission capacity, then transmission capacity is improved, but power loss and gain variations increase
Solution Approach 1:
The patent employs feedback mechanisms where the reception apparatus monitors the actual transmission quality of each spatial mode and uses this information to adjust digital signal processing parameters in real-time. This feedback loop allows the system to compensate for power loss and gain variations in high-order modes by adapting processing parameters based on actual measured performance, thereby maintaining stable transmission capacity despite energy losses
Solution Approach 2:
The patent applies preliminary action by performing pre-characterization of spatial modes and pre-adjustment of processing parameters before transmission begins. The system预先 (in advance) identifies the loss characteristics of each mode and configures appropriate equalization and compensation parameters beforehand, enabling high-order modes to be transmitted with minimal real-time adjustment and reduced power loss impact
3Measurement precision
If digital signal processing is applied to separate spatial modes, then signal separation is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the complex task of multi-mode signal separation into independent mode-specific processing channels. Each spatial mode is processed separately through dedicated digital signal processing units, allowing complex separation algorithms to be applied to individual modes without overwhelming the entire system. This modular segmentation reduces overall device complexity while maintaining high signal separation precision across all modes
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 reduces information errors in optical signals transmitted through mode-multiplexing by enhancing signal separation and transmission characteristics, particularly in spatial channels with poor performance, thereby increasing the transmission capacity and distance.
Implementation Method 1
a mode-multiplexed signal that is excitable in at least M modes
Implementation Method 2
an LP01 mode serving as a fundamental mode and an LP11 mode serving as a high-order mode are excited
Implementation Method 3
uses digital signal processing to separate the signal
Implementation Method 4
The above processing can be modeled as a 2×2 multiple-input multiple-output (MIMO) system used in a wireless communication system
Implementation Method 5
A single-mode fiber is used as an optical fiber underlying the current large-capacity optical networks
Data Source
AI summary
An optical transmission system including: N transmitters, each of the N transmitters being configured to convert one of N electrical signals indicating data sequences different from one another into an optical signal; a signal generator configured to cause N optical splitters to split the N optical signals output from the N transmitters to convert the N optical signals into M optical signals; a multiplexer configured to convert the M optical signals converted by the signal generator into one mode-multiplexed signal that is excitable in at least M modes; a demultiplexer configured to convert the mode-multiplexed signal converted by the multiplexer into M optical signals; M receivers, each of the M receivers being configured to convert one of the M optical signals converted by the demultiplexer into the electrical signal; and a signal detector configured to perform signal separation on the M electrical signals converted by the M receivers to extract the N data sequences.