FSO Network Node Wavelength Selective Devices

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Free Space Optic (FSO) networks face reliability issues due to sensitivity to environmental conditions like haze, fog, and line-of-sight blockages, which limit their use in communication technologies, and existing solutions increase costs and introduce security and synchronization challenges with electrical signal conversions.

Innovation Solution

Implementing a FSO network node with wavelength division multiplexing (WDM) technology that allows for adding and dropping wavelengths in the optical domain, using wavelength selective devices to manage multiplexed signals and avoid optical-to-electrical conversions, thereby enhancing link reliability and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If FSO links are used to provide high-capacity transport, then bandwidth and data rate are improved, but reliability deteriorates due to sensitivity to environmental conditions

Engineering Contradiction:

ImprovebandwidthVSAvoidlink availability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the operational parameters of the FSO system by implementing wavelength division multiplexing with multiple wavelength channels. This allows the system to transmit multiple signals simultaneously at different wavelengths, increasing bandwidth while using wavelength-selective devices to manage and differentiate channels, thereby improving both productivity and reliability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If redundancy links and signal repeaters are added to improve reliability, then link availability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelink availabilityVSAvoidnetwork configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functional network nodes that can operate in different modes (transparent, optical-electrical-optical conversion, wavelength routing) depending on network requirements. The wavelength-selective devices serve multiple purposes: channel separation, signal routing, and enabling both simple and complex network topologies within the same infrastructure, reducing overall system complexity while maintaining high reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces wavelength-selective devices as intermediary components that enable flexible signal management without requiring full optical-electrical-optical conversion at every node. These devices act as mediators that can selectively route different wavelength channels, providing redundancy and repeater functions while maintaining optical domain operation and reducing device complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If optical-to-electrical conversion is performed to enable signal processing, then adaptability is improved, but loss of time and synchronization issues occur

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidconversion delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the signal processing functions by separating wavelength-selective operations (performed in optical domain) from electrical signal processing. This segmentation allows most network functions to operate in the optical domain without conversion delays, while enabling electrical processing only where absolutely necessary, thus reducing time loss while maintaining adaptability

Inventive Principle:

Principle #1Segmentation

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 improves the reliability of FSO network transmissions by maintaining signals in the optical domain, reducing interference, and increasing bandwidth efficiency, while enabling full duplex communication and mitigating link failures through adaptive wavelength management.

Implementation Method 1

a first wavelength selective device configured to drop a first subset of wavelengths from the first set of multiplexed wavelengths

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS20250023638A1Free space optic network

Publication Date: 2025.01.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present application relates to a free space optic (FSO) network node that includes a first receiving module configured to receive a first FSO signal comprising a first set of multiplexed wavelengths from a first direction and a second receiving module configured to receive a second FSO signal including a second set of multiplexed wavelengths from a second direction. The FSO network node further includes a first wavelength selective device configured to drop a first subset of wavelengths from the first set of multiplexed wavelengths and a second wavelength selective device configured to drop a second subset of wavelengths from the second set of multiplexed wavelengths. The present application also relates to another FSO network node, a method and a FSO ring network.