Optical Signal Transmission via CWDM Splitter and Filter
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Solution Overview
Problem
There is a need for a simple method to transmit both digital and analog signals using a single infrastructure in optical networks, particularly in passive optical networks, where existing solutions often require separate infrastructure for each type of signal and lack efficient signal separation techniques.
Innovation Solution
The method involves transmitting signals in different frequency ranges using optical fibers, employing CWDM-splitter devices and periodic transfer functions in filters to separate and filter signals, allowing for the simultaneous use of a single network for both analog and digital signals, with the ability to block specific frequency ranges to reduce noise and enable easy installation across different network parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate infrastructure is used for digital and analog signals, then signal transmission reliability is improved, but device complexity and infrastructure cost increase
Solution Approach 1:
The patent combines digital and analog signal transmission into a single optical infrastructure using wavelength division multiplexing. Different wavelength ranges (e.g., 1530-1565nm for digital, 1570-1610nm for analog) are transmitted simultaneously over the same optical fiber, eliminating the need for separate infrastructure while maintaining signal integrity through spectral separation.
Solution Approach 2:
The patent introduces wavelength division multiplexing filters and optical filters as intermediary devices that separate digital and analog signals based on their different wavelength ranges. These filters act as mediators that enable simultaneous transmission on a single fiber while preventing signal interference, thus maintaining reliability without requiring separate physical paths.
2Device complexity
If a single infrastructure is used for both digital and analog signals, then device complexity is reduced, but signal separation and noise reduction become more difficult
Solution Approach 1:
The patent applies local quality by assigning specific wavelength ranges to specific signal types: digital signals occupy 1530-1565nm while analog signals occupy 1570-1610nm. This spectral segmentation allows each signal type to have its own designated frequency space, making separation straightforward through wavelength-selective filtering rather than requiring complex temporal or spatial separation techniques.
Solution Approach 2:
The patent changes the frequency/wavelength parameter to differentiate between digital and analog signals. By transmitting digital signals in one wavelength range and analog signals in another wavelength range on the same optical fiber, the system transforms the single-parameter transmission into a multi-parameter system where wavelength serves as the primary differentiation parameter, simplifying signal separation.
3Productivity
If wavelength division multiplexing is implemented, then transmission capacity is improved, but filter precision requirements increase
Solution Approach 1:
The patent uses coarse wavelength division multiplexing (CWDM) with relatively wide wavelength channels (e.g., 20nm spacing) compared to dense WDM. This partial implementation of WDM provides sufficient transmission capacity enhancement while requiring less precise filters than full WDM would demand. The filter precision requirement is reduced by accepting larger wavelength spacing between channels.
Solution Approach 2:
The patent segments the optical spectrum into distinct wavelength bands for different signal types, with guard bands between them. This segmentation creates clear separation zones that reduce the precision requirements for filtering, as the filters only need to distinguish between widely spaced wavelength ranges rather than closely spaced channels.
4Object-affected harmful factors
If frequency filtering is applied to block certain signals, then noise level is reduced, but transmission flexibility decreases
Solution Approach 1:
The patent implements dynamic wavelength assignment where the allocation of wavelength ranges to digital or analog signals can be flexibly configured based on network demands. The optical filters can be repositioned or reconfigured to accommodate different signal types in different wavelength slots, allowing the system to adapt to changing transmission requirements while maintaining noise reduction through frequency separation.
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 effectively utilizes a single infrastructure for both digital and analog signals, enhancing transmission capacity and reducing noise levels, while allowing for easy deployment and maintenance by using identical devices in different network parts, ensuring compatibility across various wavelengths.
Implementation Method 1
transmitting via a first transmission path a first signal in a first frequency range
Implementation Method 2
The first transmission path and/or the second transmission path may be optical fibers, for instance glass fibers or plastic fibers
Implementation Method 3
The separation of the signals can be done using comparably simple optical devices, for instance a CWDM-splitter (Coarse Wavelength Division Multiplexing)
Implementation Method 4
the first signal is filtered using a first device that has a first transfer function according to which signals in the first frequency range are transmitted... the first transfer function is such that the first device allows the transmission of signals in the second frequency range and blocks transmission of signals in at least one frequency range
Data Source
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AI summary
Method and optical system for the transmission of signals Described is a method for the transmission of the signals, comprising: - transmitting via a first transmission path (46) a first signal (V1) in a first frequency range and a second signal (V2) in a second frequency range, - the first frequency range is different from the second frequency range, - the first signal (V1) is the same as the second signal (V2).