Focal Plane Array Lidar With In-Pixel Processing
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Solution Overview
Problem
Existing LIDAR technologies face challenges such as restricted beam steering in optical phased arrays, complex calibration requirements, and significant optical losses, which limit their practical application and efficiency.
Innovation Solution
The integration of a focal plane array (FPA) with in-pixel processing capabilities and silicon photonics technology, enabling FMCW coherent detection and allowing for a wide two-dimensional field of view, reduced optical loss, and operation without calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical phased arrays are used for beam steering, then LIDAR can achieve directional scanning, but the beam steering is restricted and requires complex calibration
Solution Approach 1:
The patent replaces the mechanical/optical phased array beam steering system with a scanning mirror or galvanometer mechanism. This substitution eliminates the need for complex electronic phase control and calibration of multiple optical elements, while still achieving directional beam steering through mechanical angular deflection. The single moving mirror requires far less calibration than an optical phased array with dozens of controllable elements.
2Reliability
If conventional LIDAR systems are used, then basic ranging is achieved, but optical losses are significant and limit detection sensitivity
Solution Approach 1:
The patent extracts and removes unnecessary optical components from the LIDAR system, such as beam expanding optics, complex relay lenses, and multiple dichroic mirrors. By taking out these components that contribute to optical losses, the system maintains basic ranging functionality while significantly reducing overall optical attenuation and improving detection sensitivity.
Solution Approach 2:
The patent merges multiple optical functions into fewer integrated components. For example, the transmitter and receiver optics are combined around a single scanning mirror, and detection functions are integrated at the focal plane. This consolidation reduces the number of optical interfaces and alignments required, thereby minimizing cumulative optical losses.
3Measurement precision
If high-performance LIDAR systems are developed, then range and depth accuracy are improved, but the system size and cost increase
Solution Approach 1:
The patent transitions from a two-dimensional optical path layout to a three-dimensional compact arrangement by folding the optical path using the scanning mirror and arranging components in layers along the optical axis. This dimensional reorganization allows high-performance optics and detectors to be positioned in a compact footprint while maintaining the required optical path lengths for accurate ranging.
Solution Approach 2:
The patent implements a nested arrangement where the receiver optics are positioned within the transmitter optical path, and the focal plane array is integrated at the common focal point. This nesting allows multiple functional elements to occupy overlapping or adjacent spaces, dramatically reducing the overall system footprint while preserving depth accuracy through proper optical design.
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 enhances the range, depth accuracy, and field of view of LIDAR systems, reduces costs and physical footprint, and enables the development of high-volume, compact, and energy-efficient LIDAR systems.
Implementation Method 1
the optical switch includes a micro-ring resonator. Each of the in-processing circuits includes control circuitry configured to set a resonance wavelength of the optical switch
Implementation Method 2
Each of the plurality of pixels includes a grating coupler, a photodetector, and a reflector
Implementation Method 3
Each of the plurality of pixels includes a grating coupler, a photodetector, and a reflector configured to reflect light toward the back side of the semiconductor substrate
Implementation Method 4
Each of the plurality of pixels includes a grating coupler, a photodetector, and a reflector
Data Source
AI summary
A Light Detection and Ranging (LIDAR) system includes a transmitter configured to transmit a frequency modulated continuous wave (FMCW) signal to an environment of the LIDAR system, a receiver configured to receive, from a target in the environment, a return signal in response to transmitting the FMCW signal, a focal plane array (FPA) coupled to at least one of the transmitter and the receiver, the FPA including a two-dimensional array of pixels, and a circuit included in the FPA and configured to control each of the two-dimensional array of pixels to at least one of: (i) transmit the FMCW signal to the environment through the two-dimensional array of pixels and (ii) receive the return signal through the two-dimensional array of pixels.