LiDAR Photonic Chip Waveguide Positioning for Optical Coupling
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Solution Overview
Problem
The minimum optical coupling efficiency of echo signals in LiDAR systems is low due to the walk-off effect, which affects light collection efficiency and can cause loss of signal detection, impacting overall performance.
Innovation Solution
A LiDAR design that includes a lens and a photonic chip with receiving waveguide core layers, where the first end surface of the waveguide core layers is positioned closer to the lens than the focal plane, improving the area ratio of the light spot incident on the waveguide core layers and enhancing optical coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first end surface of the receiving waveguide core layer is designed to be coplanar with the focal plane of the lens, then the structure is simple and easy to manufacture, but the optical coupling efficiency of the echo signal is low due to the walk-off effect
Solution Approach 1:
The patent introduces a new spatial dimension by positioning the first end surface of the receiving waveguide core layer at a specific distance from the focal plane of the lens along the optical axis. This dimensional adjustment allows the light spot to be properly coupled into the waveguide core layer despite the walk-off effect, resolving the contradiction between structural simplicity and optical coupling efficiency.
Solution Approach 2:
The patent changes the positional parameter of the receiving waveguide core layer relative to the lens focal plane. By setting a specific distance between the first end surface of the waveguide core layer and the focal plane, the patent optimizes the optical coupling efficiency while maintaining manufacturing feasibility.
2Adaptability or versatility
If the scanning device deflects the detection signal direction, then the LiDAR can perform scanning and imaging functions, but the scanning device shifts by an angle during time of flight causing the walk-off effect that reduces light collection efficiency
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning the receiving waveguide core layer at a specific distance from the focal plane before the echo signal arrives. This pre-positioning compensates for the anticipated walk-off effect during the time of flight, ensuring that the light spot is properly coupled into the waveguide core layer despite the scanning device's angular shift.
3Length of moving object
If the detection distance increases, then the LiDAR can detect more distant targets, but the walk-off effect becomes more significant causing the minimum optical coupling efficiency to approach 0
Solution Approach 1:
The patent performs preliminary action by pre-configuring the receiving waveguide core layer position at a specific distance from the focal plane. This preliminary positioning ensures that regardless of the detection distance and associated walk-off effect magnitude, the light spot will be properly coupled into the waveguide core layer, maintaining optical coupling efficiency across varying detection distances.
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 design improves the optical coupling efficiency of echo signals, thereby enhancing the light detection performance of LiDAR systems by increasing the area of the light spot incident on the waveguide core layers, reducing signal loss, and maintaining performance across varying detection distances.
Implementation Method 1
a light spot formed by the echo signal output by the lens
Implementation Method 2
two or more receiving waveguide core layers embedded in the cladding layer
Data Source
AI summary
This application discloses a LiDAR and a mobile device, where LiDAR includes a lens and a photonic chip, an optical axis of the lens extends along a first preset direction; the photonic chip and the lens are spaced apart along the first preset direction, the photonic chip includes a cladding layer and multiple receiving waveguide core layers, all the receiving waveguide core layers are located at an end of the cladding layer that is closer to the lens and are spaced apart along a second preset direction, each receiving waveguide core layer has a first end surface and a second end surface opposite to each other, the first end surface is closer to the lens than the second end surface; and there is a distance between a first end surface of at least one receiving waveguide core layer and a focal plane of the lens.