Active Optical Beat Interference Remover for RFoG Networks
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Solution Overview
Problem
Conventional RFoG optical communication networks suffer from optical beat interference (OBI) due to the simultaneous transmission of signals from lasers with nearly identical wavelengths, leading to interference that can prevent communication until collisions pass, severely limiting throughput and being undesirable, especially with protocols like UDP.
Innovation Solution
An active splitter/combiner apparatus is used to receive upstream optical signals, convert them to electrical signals, combine these signals, and then convert them back to optical signals, avoiding OBI by processing each signal separately before recombining them, and an optical power splitter is used to split downstream signals for distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ONUs transmit simultaneously using lasers with nearly identical wavelengths, then network capacity and throughput are improved, but optical beat interference occurs causing communication failures
Solution Approach 1:
The patent introduces an intermediary device (optical beat interference remover) that receives the combined optical signal from multiple ONUs, converts it to electrical signals, processes it through a filter to remove beat interference, and then converts it back to optical signals for transmission to the cable modem termination system. This intermediary processing step eliminates the harmful beat interference while preserving the useful data signals, thereby maintaining both high network throughput and communication reliability.
2Device complexity
If conventional passive optical networks are used without active signal processing, then device complexity is reduced, but optical beat interference from simultaneous transmissions cannot be removed
Solution Approach 1:
The patent introduces an intermediary device (optical beat interference remover) that receives the combined optical signal from multiple ONUs, converts it to electrical signals, processes it through a filter to remove beat interference, and then converts it back to optical signals for transmission to the cable modem termination system. This intermediary processing step eliminates the harmful beat interference while preserving the useful data signals, thereby maintaining both high network throughput and communication reliability.
3Reliability
If collision avoidance protocols are implemented to prevent simultaneous transmissions, then optical beat interference is avoided, but network productivity and data throughput are severely limited
Solution Approach 1:
The patent converts the harmful optical beat interference into a manageable electrical signal domain problem. By photodetecting the combined optical signal and applying electrical filtering, the system removes the interference that would otherwise require complex protocol management. This allows multiple ONUs to transmit simultaneously without collision avoidance protocols, thereby maintaining high network throughput while ensuring transmission reliability through active interference removal.
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 solution effectively removes OBI, allowing multiple ONUs to transmit concurrently without interference, enhancing network throughput and reliability across various protocols.
Implementation Method 1
an optical-to-electrical converter configured to convert incoming optical signals to electrical signals
Implementation Method 2
an electrical-to-optical converter configured to convert the combined electrical signals back to an optical signal
Data Source
AI summary
Methods and apparatus for removing beat interference from the splitting and/or combining of signals. In one embodiment, an active splitter/combiner receives multiple input optical signals from downstream communication resources via a number of individual point-to-point links. Each input optical signal is converted to an electric signal (which, unlike the input optical signals, do not share a characteristic wavelength). The resulting electrical signals can be combined without introducing beat interference. Once combined, the resulting aggregate signal is converted back to an optical format for transmission via the optical network. Various other aspects of the present disclosure are directed to active splitting of optical signals.