Thermally Driven Optical Switch for Passive Networks

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Solution Overview

Problem

Existing optical switches for routing optical signals in passive optical networks require electrical power, which is not readily available, necessitating an alternative means for routing optical signals without electrical power sources.

Innovation Solution

A thermally driven optical switch utilizing a light mill with thermally insulated vanes that rotate due to temperature gradients established by illumination, allowing optical signals to be routed without electrical power, using a light director to adjust the signal path based on the light mill's motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical power is provided to optical switches, then switching functionality is achieved, but power availability becomes limited in passive optical networks

Engineering Contradiction:
Improveswitching functionalityVSAvoidelectrical power requirement
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces electrical actuation mechanisms with a purely optical actuation mechanism. A light mill (radiometer) uses optical radiation pressure and thermal effects to rotate mechanical components that direct optical signals, eliminating the need for electrical power sources while maintaining switching functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical switch uses the optical signal itself to actuate the switching mechanism. The control optical beam directly drives the light mill, which in turn directs the transmission beam, creating a self-contained system that requires no external electrical power and uses the optical energy already present in the system.

Inventive Principle:
Principle #25Self-service

2Temperature

If thermal insulation is applied to vane sides, then temperature gradient efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature gradientVSAvoidvane construction
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies thermal insulation selectively only to the sides of the vanes that are not illuminated by the control beam. This localized application of thermal insulation maintains the temperature gradient where needed while minimizing the overall complexity of manufacturing, as only specific surfaces require insulation treatment.

Inventive Principle:
Principle #3Local quality

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

Enables the efficient routing of optical signals in passive optical networks without the need for electrical power, providing a reliable and power-independent solution for optical signal switching.

Implementation Method 1

the first side absorbs more light energy than the second side

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

establishing a temperature gradient from the second side to the first side

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 3

having a first side and a second side which are thermally insulated from one another

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

the light director is arranged so as to direct a transmission beam carrying the transmission signal

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4094105B1Optical switch and optical routing method and system
Publication Date: 2024.08.14 BRITISH TELECOM PLC
  • EP4094105B1 patent drawingFigure 1A~2
  • EP4094105B1 patent drawingFigure 3A~3B2
  • EP4094105B1 patent drawingFigure 4A~4B2

AI summary

An optical switch is proposed, for routing an optical transmission signal according to an optical control signal, comprising: one or more optical control ports; three or more optical transmission ports; a light director; and a thermally driven light mill; wherein the light mill and the light director are arranged with respect to each other, to the one or more control ports and to the three or more transmission ports such that: illumination of a respective one of the one or more control ports by a control beam carrying the control signal drives the light mill to rotate towards a respective position in which the light director is arranged so as to direct a transmission beam carrying the transmission signal, entering the switch via a respective one of the transmission ports, to exit the switch via a respective other of the transmission