Photonic Integrated Circuit Inspection for Laser Linewidth Control
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Solution Overview
Problem
Existing photonic integrated circuits used in applications like autonomous vehicles and LiDAR systems face challenges in achieving high-depth, high-precision, and high-resolution 3D imaging due to variations in laser light intensity, line width, and linearity, which affect detection and range-finding capabilities.
Innovation Solution
A photonic integrated circuit and inspection method that includes splitting laser light into multiple sub-laser lights, modulating frequencies, coupling them to inspect interference frequency spectra, and adjusting power or line width based on these spectra to ensure consistency with predetermined parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser light parameters (intensity, line width, linearity) are not precisely controlled, then the photonic integrated circuit can be manufactured with simpler processes, but the detection precision and range-finding capability deteriorate
Solution Approach 1:
The patent introduces an inspection unit as an intermediary component that includes a reference light path with beam splitters and photodetectors. This intermediary system measures the actual laser light parameters (intensity, line width, linearity) and provides feedback signals to control units, which then adjust the laser parameters to match predetermined specifications, thereby resolving the contradiction between manufacturing precision and device complexity
Solution Approach 2:
The patent implements a closed-loop feedback system where the inspection unit continuously monitors laser light parameters and sends feedback signals to control units. The control units adjust the laser parameters based on this feedback to maintain predetermined specifications, enabling precise control without requiring complex manual intervention or over-engineering the manufacturing process
2Measurement precision
If inspection methods are added to verify laser light parameters, then detection precision and range-finding capability are improved, but the device complexity increases
Solution Approach 1:
The inspection unit is designed with multi-functionality, serving both as a measurement device for laser parameters and as a feedback source for control. The same reference light path and photodetectors are used to measure multiple parameters (intensity, line width, linearity) simultaneously, reducing the need for separate inspection systems for each parameter and thereby limiting the increase in device complexity
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
The method allows for precise verification and adjustment of laser light power, line width, and linearity, ensuring high-quality 3D imaging and reliable detection in applications like autonomous vehicles and LiDAR systems.
Implementation Method 1
coupling the first sub-laser light being modulated and the second sub-laser light to generate a first coupling light; inspecting an interference frequency spectrum of the first coupling light
Data Source
AI summary
An inspection method of a photonic integrated circuit, the inspection method includes steps of: generating a main laser light; splitting the main laser light into a detection laser light and a reference laser light; splitting the reference laser light into a first laser light and a second laser light; splitting the first laser light into a first sub-laser light and a second sub-laser light; modulating a frequency of the first sub-laser light; coupling the first sub-laser light being modulated and the second sub-laser light to generate a first coupling light; inspecting an interference spectrum of the first coupling light; and adjusting a power or a linewidth of the main laser light according to the interference spectrum. The disclosure also discloses a photonic integrated circuit.