Switched Optical Phased Array LiDAR Power Reduction
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Solution Overview
Problem
High power consumption and complexity in large-scale optical phased array (OPA) LiDAR systems for autonomous driving due to the need for numerous phase shifters and controlling circuits, which generates heat and control complexity, especially in wide temperature ranges, and existing solutions like multiple OPA chips or sequential connection are not scalable in terms of cost and system complexity.
Innovation Solution
A LiDAR system with integrated photonics OPA featuring a large number of 1D scanning antenna arrays, where only one array's phase shifters are actively adjusted at a time to connect to a shared light source, utilizing an optical switching network, beam splitters, and phase shifter arrays to reduce power consumption and complexity, enabling 2D beam steering by switching and routing light between arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of antennas and phase shifters are used to achieve high-resolution 2D beam scanning, then beam steering precision and resolution are improved, but power consumption and system complexity increase dramatically
Solution Approach 1:
The patent divides the 2D antenna array into multiple 1D antenna sub-arrays, where each sub-array can be independently controlled and switched. This segmentation allows the system to activate only the necessary sub-arrays for current scanning requirements, reducing the number of simultaneously active phase shifters and lowering overall power consumption while maintaining beam steering precision.
Solution Approach 2:
The patent implements sequential switching between different 1D antenna sub-arrays, activating them in periodic cycles rather than simultaneously. Each sub-array is activated for a specific time period to cover different angular ranges, achieving complete 2D scanning coverage through time-multiplexed operation, which significantly reduces instantaneous and average power consumption.
2Measurement precision
If a large number of phase shifters and controlling circuits are used to achieve high-resolution beam scanning, then beam steering precision is improved, but control complexity and heat generation increase
Solution Approach 1:
The control system is segmented to match the segmented antenna sub-arrays, with each sub-array having its own simplified phase shifter and control circuit. This reduces the complexity of individual control units and allows for modular control architecture, making the overall system more manageable despite the large total number of antennas.
Solution Approach 2:
The patent merges the control of multiple antenna sub-arrays through a centralized switching mechanism that sequentially activates different sub-arrays. This combining approach allows a single control unit to manage multiple sub-arrays over time, reducing the total number of independent control circuits needed while maintaining precise beam steering capability.
3Adaptability or versatility
If multiple OPA chips are used to expand scanning coverage, then field of view is improved, but system complexity and cost increase
Solution Approach 1:
Instead of expanding horizontally by adding more OPA chips side-by-side, the patent extends the scanning capability by utilizing the temporal dimension through sequential switching of multiple 1D sub-arrays. This time-multiplexed approach achieves equivalent 2D scanning coverage without the complexity of synchronizing multiple independent OPA chips, effectively adding scanning dimension through time rather than space.
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
Significantly reduces power consumption and complexity by only actively powering and adjusting phase shifters in one 1D array at a time, allowing for scalable and efficient 2D beam steering, making large-scale OPA-based LiDAR products feasible.
Implementation Method 1
An optical phased array device is generally made of many antenna units which are arranged in one- or two-dimensional array and are individually or group tunable in phase and sometimes amplitude in order to form a specific output beam pattern through interference effect.
Implementation Method 2
The photonic waveguides can be made on chip with many optical material systems such as silicon-on-insulator, doped silica, silicon nitride, indium phosphide, lithium niobate and etc.
Implementation Method 3
A typical thermo-optics or free-carrier absorption based phase shifters requires about 10 mW for it shifting
Implementation Method 4
A typical thermo-optics or free-carrier absorption based phase shifters requires about 10 mW for it shifting
Data Source
AI summary
A switched optical phased array based beam steering LiDAR (light detection and ranging) system includes an integrated photonics optical phased array (OPA) that includes an optical switching network for selectively connecting a large number of 1D scanning (in a first direction or field-of-view) antenna arrays to a light source. Each array is configured to emit light in a predefined angle of a second direction or field-of-view and can be switched individually to connect to the light source. At any given time, the phase shifters of only one such array, i.e. the one that is switched to connect the light source, are actively adjusted by the control circuits, so that the active power consumption is greatly reduced. The LiDAR system also includes a photo sensor receiver, other control and signal processing circuits, and other necessary optical and mechanical components.