Star Coupler LIDAR Scanning with Off-Axis Return Detection
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Solution Overview
Problem
Conventional LIDAR systems are constrained by the finite speed of light, limiting scan rates and requiring prolonged staring times to detect distant objects, and existing integrated beam-steering solutions are bulky and inefficient.
Innovation Solution
An optical scanning method using a star coupler that integrates transmission and reception on the same platform, allowing simultaneous detection of return light without additional optical elements, by distributing the input beam across an array of output waveguides and using controllable phase shifts for beam steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LIDAR systems use mechanical beam steering to detect distant objects, then detection capability is improved, but system size, weight, and complexity increase
Solution Approach 1:
The patent replaces mechanical beam steering with a solid-state phased array system that uses electronic phase control to steer beams. The phased array of optical emitters enables beam steering through constructive interference controlled by relative phase delays, eliminating moving mechanical components while maintaining detection capability for distant objects
Solution Approach 2:
The patent integrates both transmission and reception functions into a single shared optical path using the same phased array elements. The system can transmit beams and detect return light simultaneously through the same physical structure, reducing overall system complexity compared to separate mechanical steering systems
2Measurement precision
If the system stares in the same direction to detect distant objects, then detection of distant targets is improved, but scan rate decreases due to finite speed of light
Solution Approach 1:
The patent divides the detection task into multiple simultaneous beams using a phased array with multiple elements. Each element or group of elements can be steered to different directions simultaneously, allowing the system to detect multiple targets at different distances and locations at the same time, thereby increasing scan rate while maintaining detection capability
Solution Approach 2:
The patent transitions from sequential scanning in one dimension to parallel multi-directional scanning by utilizing the spatial distribution of phased array elements. By controlling phase delays across multiple elements, the system creates multiple beams simultaneously in different directions, effectively adding a spatial dimension to the detection process
3Difficulty of detecting and measuring
If additional optical elements are used to separate send and return signals, then signal processing is improved, but system complexity and signal loss increase
Solution Approach 1:
The patent merges the transmission and reception paths into a single integrated optical structure. The same phased array elements and optical components are used for both sending beams and detecting return light, eliminating the need for separate optical paths and additional beam separating elements. This integration reduces system complexity and avoids signal losses associated with multiple optical interfaces
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
Enables faster scan rates and efficient detection of multiple targets by concurrently processing send and return signals, reducing system size and weight through integrated beam steering without signal separation losses.
Implementation Method 1
The waveguides and slab waveguide region are arranged so that the optical power incident on any input waveguide will couple to the output array in such a manner that it is distributed over all of the waveguides in the output array
Implementation Method 2
The electromagnetic waves scattered respectively by each of these emitting elements interfere with each other. The collective interference creates a directed beam
Implementation Method 3
Each path is then directed to an individual emitting element. The electromagnetic waves scattered respectively by each of these emitting elements interfere with each other
Implementation Method 4
A return beam of light is detected after reflecting from external objects
Implementation Method 5
By adjusting the relative delay or phase between elements, the angle of this directed beam can be controlled
Implementation Method 6
The electromagnetic waves scattered respectively by each of these emitting elements interfere with each other. The collective interference creates a directed beam
Implementation Method 7
Return light that reenters the beam-steering system and traverses its original optical path in reverse will come to a focus on the end of the center input waveguide
Implementation Method 8
Return light that reenters the beam-steering system and traverses its original optical path in reverse will come to a focus on the end of the center input waveguide
Data Source
AI summary
A LIDAR system or the like uses a star coupler to distribute an input light beam over a steerable array. The input light beam is injected through an input signal waveguide on the input side of the star coupler. The light returning after reflecting from external objects is directed back through the star coupler to one or more waveguides on the input side. Return light is detected in one or more waveguides on the input side that are displaced from the input signal waveguide. In embodiments, the beam direction of the steerable array changes during the round-trip transit time of the returning light. This causes the returning light to arrive off-axis, which in turn causes it to couple into one or more of the displaced input-side waveguides instead of coupling back into the input signal waveguide.