Optical Alignment System for Free Space Communication

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Solution Overview

Problem

Free space optical communication systems, such as Li-Fi, face challenges in maintaining alignment due to environmental factors like wind, thermal expansion, and weather, which can lead to misalignment and data loss.

Innovation Solution

The system employs an adjustment mechanism to intentionally generate predetermined and repetitive motions of the optical beam path between units, using piezoelectric actuators or MEMS-controlled mirrors, to preemptively correct potential misalignments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If free space optical communication units are mounted at elevated positions to prevent interference, then signal path obstruction is reduced, but alignment stability deteriorates due to environmental factors like wind and thermal expansion

Engineering Contradiction:

Improvesignal obstructionVSAvoidalignment stability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The system performs preliminary alignment corrections by detecting potential misalignment trends and applying compensatory movements before complete misalignment occurs. The alignment mechanism proactively adjusts the optical beam path based on detected drift patterns, preventing data loss rather than reacting after alignment is lost.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the alignment status by detecting the position of the optical beam relative to the detector using unit detectors. This feedback information is used to control the alignment mechanism (piezoelectric actuators or MEMS mirrors) to maintain proper alignment despite environmental disturbances.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If alignment correction mechanisms are added to maintain beam alignment, then alignment stability is improved, but device complexity increases

Engineering Contradiction:

Improvealignment stabilityVSAvoidsystem complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical alignment adjustment mechanisms with piezoelectric actuators or MEMS (micro-electromechanical systems). These micro-scale devices provide precise control of the optical beam path with minimal mechanical complexity, enabling fine adjustments to compensate for alignment drift.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment mechanism changes physical parameters (position, angle) of optical components using piezoelectric effects or MEMS actuation. By controlling the deformation or position of these components, the system dynamically adjusts the optical beam path to maintain alignment without complex mechanical structures.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If predetermined repetitive motions are applied to the beam path to detect potential misalignment, then detection precision is improved, but energy consumption increases

Engineering Contradiction:

Improvemisalignment detection precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system applies small, predetermined repetitive motions (circular or reciprocating) to the optical beam path that are minimal in amplitude but sufficient to detect potential misalignment trends. These partial motions allow the unit detectors to sense alignment changes without requiring large-scale movements, thus minimizing energy consumption while maintaining detection precision.

Inventive Principle:

Principle #16Partial or excessive action

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 prevents significant data loss by detecting and correcting potential misalignments before they occur, ensuring stable and continuous optical communication.

Implementation Method 1

The alignment mechanism comprises a plurality of piezoelectric actuators

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

one or more MEMS controlled mirrors

Methodology Applied

Scientific EffectMicro-electromechanical systems: Microelectromechanical Systems

Data Source

PatentUS12218704B2Optical alignment system for optical communication devices

Publication Date: 2025.02.04 SIGNIFY HOLDING BV

AI summary

A method and optical system for preemptively correcting a potential future misalignment of an optical communication beam between a plurality of free space optical (FSO) units or Light Fidelity (Li-Fi) units by intentionally generating predetermined and repetitive motions of the beam path between the units using an adjustment mechanism. In some examples the predetermined motion is a circular motion or a reciprocating and/or translating motion. The predetermined motions can be implemented by an adjustment mechanism which can include a plurality of piezoelectric actuators or one or more MEMS controlled mirrors or micro-lenses.