Remote Node Optical Switching for Central Office Redundancy
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Solution Overview
Problem
Existing fiber optic communication networks lack effective redundancy mechanisms to prevent service outages due to fiber cuts or site failures, particularly at the central office, which is a single point of failure.
Innovation Solution
Implementing a remote node with a two-by-two optical switch, photodiode, and capacitor to switch between feeder fibers from two central offices, ensuring continuous communication by switching to a backup fiber when the primary fiber fails, and using a demultiplexer with an arrayed wavelength grating for signal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single central office is used to provide optical signals, then the network structure is simple, but the reliability is low due to single point of failure
Solution Approach 1:
The patent implements preliminary redundancy by establishing backup feeder fiber connections from multiple central offices to the remote node before any failure occurs. The optical switch is pre-configured with multiple input ports corresponding to different central offices, and the system maintains standby connections that can be activated immediately upon detecting a failure in the primary connection, thereby improving reliability without requiring complex real-time decision-making infrastructure
Solution Approach 2:
The patent segments the network dependency by dividing the single central office connection into multiple independent feeder fiber connections from different central offices. This segmentation allows the remote node to receive optical signals from alternative sources if one connection fails, effectively breaking the single point of failure while maintaining a relatively simple overall network architecture through modular connection design
2Productivity
If automatic switching mechanism is implemented, then the service continuity is improved, but the device complexity increases
Solution Approach 1:
The patent implements self-service automatic switching through a failure detection mechanism that autonomously monitors the health of optical signals from different central offices. When a failure is detected in the primary feeder fiber, the system automatically switches to a backup connection without requiring external intervention or complex control algorithms. The optical switch and monitoring equipment work together to detect failures and execute switching decisions independently, maintaining service continuity while keeping the control mechanism relatively simple
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors the status of optical signals from multiple central offices and uses this information to automatically control the optical switch. The monitoring equipment provides real-time feedback about connection health, and this feedback loop enables the switching mechanism to respond dynamically to failures, ensuring service continuity through automatic reconfiguration based on actual network conditions
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
Ensures continuous communication by automatically switching to a backup feeder fiber when the primary fails, enhancing network reliability and reducing the risk of service outages.
Implementation Method 1
The photodiode is optically coupled to the second switch output. When the first switch is switchably coupled to the first switch output, the second switch input is switchably coupled to the second switch output, and any light received by the second switch input passes out the second switch output to the photodiode.
Implementation Method 2
The capacitor is electrically coupled to the photodiode and the two-by-two optical switch. The photodiode charges the capacitor, and when the capacitor is charged to a threshold charge, the capacitor triggers the two-by-two optical switch
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A remote node (170) includes a first node input (531), a second node input (532), and an optical switch (600). The optical switch includes a first switch input (610) optically coupled to the first node input, a second switch input (612) optically coupled to the second node input, a first switch output switchably coupled to the first switch input or the second switch input, and a second switch output switchably coupled to the first switch input or the second switch input. The remote node includes a photodiode (520) optically coupled to the second switch output, and a capacitor (540) electrically coupled to the photodiode and the optical switch. When the first switch input is switchably coupled to the first switch output, the second switch input is switchably coupled to the second switch output. Light received by the second switch input passes out the second switch output to the photodiode. The photodiode charges the capacitor to a threshold charge.