Mid-Infrared Optical Phased Array for LiDAR Beam Steering

Solution Overview

Problem

Existing beam-steering technologies for mid-infrared applications are limited by mechanical components, high cost, and inefficient steering capabilities, particularly in LiDAR and countermeasure systems, where non-mechanical, compact, and high-power solutions are needed.

Innovation Solution

A monolithically integrated mid-infrared two-dimensional optical phased array using a tunable quantum cascade laser and thermo-optic phase shifting, integrated on an Indium Phosphide substrate, enables beam steering in both azimuth and elevation planes without mechanical components, utilizing a splitter region with Y-junctions and phase shifting regions for precise control of electromagnetic radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical beam-steering components are used in mid-IR systems, then beam steering capability is achieved, but device weight, complexity, and size increase

Engineering Contradiction:

Improvebeam steering capabilityVSAvoidmechanical components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical beam-steering components with a photonic integrated circuit that uses optical phase modulation. The OPA employs multiple quantum cascade laser emitters arranged in an array, with each emitter's phase independently controllable through electrical signals. This electro-optic approach eliminates moving mechanical parts while achieving the same beam steering function through constructive and destructive interference of light waves from different emitters.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If mechanical beam-steering components are used, then beam steering is achieved, but device weight and size increase

Engineering Contradiction:

Improvebeam steering capabilityVSAvoiddevice weight

Core Design Contradiction:

Ease of operationVSWeight of moving object

Solution Approach 1:

The patent replaces mechanical beam-steering components with a photonic integrated circuit that uses optical phase modulation. The OPA employs multiple quantum cascade laser emitters arranged in an array, with each emitter's phase independently controllable through electrical signals. This electro-optic approach eliminates moving mechanical parts while achieving the same beam steering function through constructive and destructive interference of light waves from different emitters.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent integrates multiple functional components into a single monolithic photonic chip. The quantum cascade laser emitters, waveguides, phase modulators, and beam combining optics are all fabricated together on the same semiconductor substrate using epitaxial growth and lithographic processing. This integration dramatically reduces the overall system weight and size compared to discrete mechanical steering components.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If conventional beam-steering technology is used, then beam steering is achieved, but cost and power consumption increase

Engineering Contradiction:

Improvebeam steering capabilityVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by stationary object

Solution Approach 1:

The patent replaces mechanical beam-steering components with a photonic integrated circuit that uses optical phase modulation. The OPA employs multiple quantum cascade laser emitters arranged in an array, with each emitter's phase independently controllable through electrical signals. This electro-optic approach eliminates moving mechanical parts while achieving the same beam steering function through constructive and destructive interference of light waves from different emitters.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent controls beam steering by changing the optical phase parameter of individual emitters through electrical modulation. By adjusting the phase difference between adjacent emitters, the direction of the combined beam can be precisely controlled without mechanical movement. This parameter-based control method is more energy-efficient than mechanical actuation while providing continuous and precise beam steering capability.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If conventional beam-steering technology is used, then beam steering is achieved, but steering range and efficiency are limited

Engineering Contradiction:

Improvebeam steering capabilityVSAvoidsteering range

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic beam steering by independently modulating the phase of each emitter in the array through electrical signals. This allows real-time, continuous adjustment of the beam direction across a wide angular range. The dynamic control capability enables rapid beam scanning and tracking without mechanical inertia limitations, providing superior steering range and responsiveness compared to conventional mechanical systems.

Inventive Principle:

Principle #15Dynamics

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

The solution provides a compact, lightweight, and high-power beam-steering device capable of steering in both azimuth and elevation planes, achieving a steering range of up to 55° and maintaining high coupling efficiency, addressing the limitations of existing technologies.

Implementation Method 1

the tunable quantum cascade laser configured to generate mid-IR electromagnetic radiation light from the active region

Methodology Applied

Scientific EffectStimulated emission: Laser

Implementation Method 2

the taper region configured to adiabatically couple the mid-IR electromagnetic radiation light from the active region into the un-doped waveguide layer

Methodology Applied

Scientific EffectAdiabatic coupling: Waveguide (optics)

Implementation Method 3

the individually controllable heaters configured to modify phase of the mid-IR electromagnetic radiation light within each of the ridge waveguides

Methodology Applied

Scientific EffectThermal-optic effect: Thermal Expansion

Implementation Method 4

the emitter gratings configured to emit the mid-IR electromagnetic radiation light from the ridge waveguides of the two or more channels

Methodology Applied

Scientific EffectDiffraction: Diffraction Grating

Data Source

PatentUS11605932B2Monolithically integrated mid-infrared two-dimensional optical phased array

Publication Date: 2023.03.14 OMEGA OPTICS

AI summary

A novel, monolithically integrated mid-IR optical phased array (OPA) structure which eliminates the wafer bonding process to achieve highly efficient surface emitting optical beam steering in two dimensions is disclosed. Since solar energy is about 15-20 times smaller than that at 1.55 μm, mid-IR is more favorable for the atmospheric transmission due to lower solar radiance backgrounds. For the beam steering, thermo-optic phase shifting is used for azimuthal plane beam steering and laser wavelength tuning is used for elevation plane beam steering. The OPA structure disclosed comprises a wavelength-tunable a QCL, a 1×32 splitter, thermo-optic phase-shifters, and sub-wavelength grating emitters. The disclosed OPA provides a low-cost, low-loss, low-power consumption, robust, small footprint, apparatus that may be used with expendable UAV swarms. A LiDAR may be created by monolithically integrating a QCD with the apparatus. Other embodiments are described and claimed.