Photonic Air Data Detection via Passive Optical Filter Array
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Solution Overview
Problem
Current air data systems, such as Pitot tubes, are prone to blockages and mechanical damages, and direct detection Doppler LiDAR systems are inefficient and computation-intensive, necessitating a robust and efficient air data measurement solution.
Innovation Solution
The implementation of integrated silicon photonics LiDAR air data detection systems using passive optical frequency spectrum decomposition for high-efficiency, low-power air data measurement, which includes a photonics chip with a passive optical filter array and optical detectors to process backscattered light and provide frequency spectrum decomposition, independent of the laser probing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct detection Doppler LiDAR systems use fringe imaging with a Fabry-Perot etalon, then air data measurement can be achieved, but light efficiency is poor (greater than 90% light wasted) and computation is intensive
Solution Approach 1:
The patent replaces the traditional Fabry-Perot etalon optical system with a photonic integrated circuit (PIC) based system. The PIC uses on-chip waveguides, gratings, and interferometers to perform the same spectral analysis function, eliminating the need for bulky mechanical optical components and reducing light loss through more efficient optical coupling and detection.
Solution Approach 2:
The patent changes the operating parameters by using a swept-wavelength laser source that scans through a range of wavelengths, combined with a spectral sensor that detects the backscattered light spectrum. This approach transforms the measurement from time-domain fringe analysis to frequency-domain spectral analysis, improving light efficiency and reducing computational complexity.
2Measurement precision
If direct detection Doppler LiDAR systems use fringe imaging with a Fabry-Perot etalon, then air data measurement can be achieved, but computation is intensive
Solution Approach 1:
The patent replaces complex computational fringe analysis with a photonic integrated circuit that performs spectral decomposition optically. The PIC's waveguides, gratings, and interferometers physically separate and detect different wavelength components, transforming a computationally intensive problem into an optical processing task that requires minimal digital computation.
Solution Approach 2:
The patent introduces a spectral sensor as an intermediary between the backscattered light and the detection system. This sensor captures the spectral information directly, serving as a mediator that converts optical frequency information into detectable signals without requiring complex computational algorithms to extract the data from fringe patterns.
3Weight of moving object
If integrated silicon photonics LiDAR air data detection systems are implemented, then size, weight, and power consumption are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges multiple discrete optical components (laser source, waveguides, gratings, interferometers, detectors) onto a single photonic integrated circuit chip. This consolidation reduces the overall system size and weight while leveraging standardized semiconductor manufacturing processes that can achieve the required precision through volume production and process control.
Solution Approach 2:
The patent changes the manufacturing approach by using standard silicon photonics fabrication processes, including CMOS-compatible techniques. This allows the system to benefit from established semiconductor manufacturing capabilities, where high precision is achieved through controlled deposition, etching, and lithography processes that are routinely performed with sub-micron accuracy in high-volume production.
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 solution offers high-resolution, high-efficiency air data measurement with low size, weight, and power consumption, suitable for various vehicles, including urban air mobility vehicles and drones, and is resilient to wavelength drifts through the use of a heater for frequency alignment.
Implementation Method 1
A passive optical filter array and optical detectors, which receive the backscattered light and provide frequency spectrum decomposition
Implementation Method 2
The heater is configured to adjust a frequency of the optical filter array to align with a frequency of the laser
Implementation Method 3
direct detection Doppler LiDAR systems based on backscattered light from air molecules
Data Source
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AI summary
A system for light detection and ranging (LiDAR) based sensing including air data detection is disclosed. The system comprises a photonics substrate comprising a passive optical filter array configured to receive backscattered light produced in a region of interest when a light beam is emitted by a laser device, and a reference beam from the laser device. The passive optical filter array includes a plurality of optical notch filters in optical communication with each other, the optical notch filters operative for frequency selection, and a plurality of optical detectors each respectively coupled to an output of one of the optical notch filters. The passive optical filter array is operative to perform frequency spectrum decomposition of the received backscattered light into a plurality of signals for data extraction and processing to determine air data parameters.