Multimode Optical Waveguide Mode Multiplexing Capacity
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Solution Overview
Problem
Current optical transmission systems face limitations in increasing transmission capacity beyond a factor of 20 without significant technical effort, as demand for bandwidth continues to grow exponentially, with existing methods like wavelength division multiplexing, polarization multiplexing, and multi-level modulation struggling to meet future demands efficiently and cost-effectively.
Innovation Solution
The method employs multimode optical waveguides with mode multiplexing, where each propagation mode is used for transmitting a signal, allowing for significant increases in transmission capacity by using mode multiplexers and demultiplexers in conjunction with wavelength division multiplexing, enabling cost-effective capacity expansion beyond traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wavelength division multiplexing and polarization multiplexing are used to increase transmission capacity, then the transmission capacity can be increased by a factor of approximately 20, but the technical effort and system complexity increase significantly
Solution Approach 1:
The patent transitions from single-mode to multimode optical waveguides, utilizing the spatial dimension by exciting and transmitting multiple propagation modes simultaneously. This dimensional change allows capacity expansion beyond the limitations of wavelength and polarization multiplexing alone, achieving higher capacity without proportionally increasing system complexity
Solution Approach 2:
The patent segments the transmission capacity by dividing it across multiple propagation modes in the multimode waveguide. Each mode can carry independent signals, effectively segmenting the total capacity into mode-specific channels that can be managed and optimized independently
2Productivity
If multi-level modulation methods are used to increase bandwidth efficiency, then more bits per symbol can be transmitted, but the optical signal-to-noise ratio requirements become increasingly difficult to meet
Solution Approach 1:
Instead of increasing modulation levels in the temporal domain, the patent exploits the spatial domain by utilizing multiple propagation modes. This dimensional shift allows achieving high capacity without the stringent optical signal-to-noise ratio requirements that plague high-order modulation schemes
3Productivity
If the number of channels is increased to meet growing capacity demand, then transmission capacity increases, but the range decreases due to increased spectral attenuation at band edges
Solution Approach 1:
The patent moves from frequency-domain multiplexing (wavelength division) to spatial-domain multiplexing (mode division). This allows adding capacity channels without extending into spectral regions with high attenuation, thereby maintaining transmission range while increasing capacity
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
This approach allows for a substantial increase in transmission capacity per fiber, overcoming the limitations of existing methods by utilizing the full potential of multimode waveguides, enabling efficient and cost-effective transmission of multiple channels over long distances with reduced interference.
Implementation Method 1
several optical transmitters generate a signal for each of the wavelengths to be transmitted and switch these signals onto the multimode optical waveguide via mode multiplexers and wavelength multiplexers, the multimode optical waveguide for each of the modes to be transmitted having its own propagation mode within the optical waveguide
Implementation Method 2
Optical transmission systems with wavelength division multiplexing currently offer the only approach for transmitting data streams with a total data rate of several terabits per second over distances of several hundred kilometers in a single transmission medium
Data Source
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AI summary
The invention relates to a method for transmitting optical information between an emitter station (7) and a receiving station (6) via a multi-mode optical wave guide (3) using a wave length multiplex method. According to the invention, several optical emitters (OS) generate a respective signal (TX) for each of the wave lengths to be transmitted, and said signals (TX) are fed to the multi-mode optical wave guide (3) in the form of a number of modes via mode multiplexers (MM) and wavelength multiplexers (WM), the multi-mode optical wave guide (3) having its own mode that can propagate within the multi-mode optical wave guide (3) for each of the modes to be transmitted and after the transmission and optionally the regeneration and/or amplification of the signal via the multi-mode optical wave guide (3), the transmitted signals are broken down via the wavelength multiplexer (WD) into groups of signals having the same wavelength and via the mode demultiplexer (MD) into signals having the same mode, and subsequently, the interference signals are extracted from the transmitted demultiplexed signals (RX), said interference signals being formed due to over coupling between the individual modes during the transmission via the multi-mode optical wave guide (3).