Optical Phased Array Beam Steering with Microlens

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Solution Overview

Problem

Existing optical phased arrays face limitations in steering optical beams due to multiple orders of diffraction, limited angle-tuning range, and polarization sensitivity, which hinder their application in directional communications.

Innovation Solution

The use of a phased array with on-chip phase shifters and vertical off-chip couplers, combined with a microlens array and a reverse beam expander, allows for concentration of light into a single diffraction order, increasing the angular tuning range while reducing the beam diameter and eliminating the need for mechanical parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phased arrays are used for beam steering, then mechanical moving parts are eliminated, but multiple orders of diffraction are emitted and angle-tuning range is limited

Engineering Contradiction:
Improvebeam steering reliabilityVSAvoidmultiple diffraction orders
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful diffraction orders by introducing a specific grating structure that confines the optical beam to a single diffraction order (zeroth order), thereby removing the harmful effect of multiple diffraction orders while maintaining the benefits of phased array beam steering without mechanical parts

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the grating period parameter to be larger than a critical value, which fundamentally alters the diffraction behavior to emit light in a single direction only. This parameter change transforms the system from producing multiple diffraction orders to producing a single confined beam, resolving the contradiction between reliability and harmful factors

Inventive Principle:
Principle #35Parameter changes

2Reliability

If phased arrays are used for beam steering, then mechanical moving parts are eliminated, but angle-tuning range is limited

Engineering Contradiction:
Improvebeam steering reliabilityVSAvoidangle-tuning range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the grating period parameter to enable a wide tuning range of the optical beam direction. By setting the grating period larger than a critical value, the system achieves both reliable single-order diffraction and extended adaptability in terms of angle-tuning range, allowing the beam to be steered across a broader angular spectrum

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional beam steering with mechanical elements is used, then beam direction can be adjusted, but speed limitations and sensitivity to shocks and vibrations occur

Engineering Contradiction:
Improvebeam direction adjustmentVSAvoidbeam steering speed
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The patent replaces the mechanical beam steering system with an optical phased array system that uses phase modulation of light waves to control beam direction. This substitution eliminates mechanical moving parts entirely, enabling instantaneous beam steering at the speed of light modulation without mechanical inertia or friction limitations, thereby dramatically improving beam steering speed

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

4Ease of operation

If conventional beam steering with mechanical elements is used, then beam direction can be adjusted, but bulky elements are added to the apparatus

Engineering Contradiction:
Improvebeam direction adjustmentVSAvoidapparatus volume
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent replaces bulky mechanical steering elements (mirrors, lenses, moving components) with a compact integrated photonic circuit implementing a phased array. This optical system confines light through waveguide structures and grating couplers, eliminating the need for large mechanical components and significantly reducing the overall apparatus volume while maintaining beam direction adjustment capability

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

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 configuration enables efficient, directional optical beam steering with a wide tuning range and reduced polarization sensitivity, facilitating high-speed and secure optical communications without mechanical components.

Implementation Method 1

application of phased arrays to beam steering has so far been prevented because they emit in multiple orders of diffraction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

concentration of light from the phased array into a single order of diffraction

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

optical means being for concentrating light from the phased array and/or expand a received beam of light

Methodology Applied
Scientific EffectBeam expansion: Lens

Data Source

PatentEP3028097B1Optical beams
Publication Date: 2021.06.30 NOKIA TECHNOLOGIES OY
  • EP3028097B1 patent drawingFigure 1~14
  • EP3028097B1 patent drawingFigure 2~4
  • EP3028097B1 patent drawingFigure 5a~5b

AI summary

Apparatuses and methods for producing and/or receiving an optical beam are disclosed, A phased array on a chip comprises phase shifters and off-chip couplers to provide phase controlled pixels. An optical system is arranged in front of the phased array. The optical system is configured to concentrate light from the phased array and/or expand a received beam of light for input into the phased array.