LIDAR Array Waveguide Receivers with Optical Frequency Shifting

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Solution Overview

Problem

Conventional LIDAR systems face challenges in detecting distant objects due to the descan lag angle, which results in reduced signal-to-noise ratio (SNR), limited scan/frame rate, and maximum range, requiring high-power analog-to-digital converters (ADCs) with large sampling rates.

Innovation Solution

The integration of array waveguide receivers (AWRs) and optical frequency shifters (OFS) into a photonic integrated circuit (PIC) architecture, which collects Rx power from distant objects using satellite waveguides and remaps target beat frequencies to the radio frequency (RF) baseband, reducing ADC bandwidth and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional LIDAR systems use traditional receivers without array waveguide integration, then the system structure is simpler, but the signal-to-noise ratio (SNR) is reduced and maximum detection range is limited

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidsystem structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates multiple waveguide receivers into an array configuration on a photonic integrated circuit, combining their signals to improve SNR. The array waveguide receivers are merged with optical frequency shifters and other components into a unified PIC architecture, enabling enhanced detection performance while managing system complexity through integration.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces optical frequency shifters as intermediary components that shift the frequency of received optical signals to intermediate frequencies before further processing. This intermediary frequency shifting enables better signal separation and processing, improving detection capability without directly increasing receiver complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional LIDAR systems increase scan/frame rate to improve productivity, then the framerate increases, but the descan lag angle increases which reduces SNR and maximum range

Engineering Contradiction:

ImproveframerateVSAvoidsignal-to-noise ratio

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent employs dynamic frequency shifting where the optical frequency shifter continuously adjusts the frequency of the local oscillator signal based on the scan rate and lag angle. This dynamic adjustment compensates for the descan effect, allowing the system to maintain high frame rates while preserving SNR and maximum detection range by adaptively correcting for the lag angle.

Inventive Principle:

Principle #15Dynamics

3Length of stationary object

If conventional LIDAR systems use high-power ADCs with large sampling rates to detect distant objects, then the maximum range increases, but the power consumption increases

Engineering Contradiction:

Improvemaximum rangeVSAvoidpower consumption

Core Design Contradiction:

Length of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent replaces the need for high-power, high-speed ADCs with an optical processing approach. By using array waveguide receivers with optical frequency shifting and optical signal processing, the system achieves long-range detection capability without requiring high-power electronic conversion. The optical domain processing reduces the burden on subsequent electronic ADCs, lowering power consumption while maintaining maximum detection range.

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 enhances the SNR, increases the maximum LIDAR range and velocity resolution, and framerate, while reducing power dissipation and system cost, enabling efficient detection of distant objects.

Implementation Method 1

an optical frequency shifter (OFS) to shift a frequency of the second LO signal to cause the second output signal to shift from within the second frequency range to within the first frequency range

Methodology Applied

Scientific EffectOptical frequency shifting:

Implementation Method 2

one or more photodetectors to: generate, based on the first waveguide signal and a first local oscillator (LO) signal, a first output signal within a first frequency range

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11808851B2Techniques for enhanced detection of distant objects

Publication Date: 2023.11.07 AEVA INC

AI summary

A system including one or more waveguides to receive a first returned reflection having a first lag angle and generate a first waveguide signal, receive a second returned reflection having a second lag angle different from the first lag angle, and generate a second waveguide signal. The system includes one or more photodetectors to generate a first output signal within a first frequency range, and generate, based on the second waveguide signal and a second LO signal, a second output signal within a second frequency range. The system includes an optical frequency shifter (OFS) to shift a frequency of the second LO signal to cause the second output signal to shift from within the second frequency range to within the first frequency range to generate a shifted signal. The system includes a processor to receive the shifted signal to produce one or more points in a point set.