Nested Interferometer for Wind Lidar
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lidar systems for measuring wind speeds over a wide range of atmospheric levels are bulky, expensive, and require multiple lasers, receivers, and telescopes, making them difficult and costly to implement, especially when trying to simultaneously measure aerosol and molecular returns with different scattering characteristics.
Innovation Solution
A dual-path length quadrature Mach-Zehnder wind lidar system that operates at multiple wavelengths, using an unequal path length interferometer with different optical path differences for each wavelength to enable simultaneous measurement of lidar returns, and includes a data processing system to determine wind speeds by analyzing the phase shifts in the interference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hybrid lidar systems use two different types of lasers, two different receivers, and expensive telescopes to measure both aerosol and molecular returns, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies a single laser source that emits multiple wavelengths (355 nm and 532 nm) to perform both molecular and aerosol measurements, replacing the need for two separate laser systems. The single receiver with wavelength-selective optics detects both types of returns, achieving multi-functionality while reducing system complexity and cost.
Solution Approach 2:
The patent merges the functions of multiple lasers, multiple receivers, and expensive telescopes into a single integrated system. By combining wavelength-selective optics with a single receiver, the system achieves the measurement capabilities of hybrid lidar systems without requiring separate optical paths and detectors for each wavelength.
2Adaptability or versatility
If filter-based systems combine Fizeau spectrometer with Fabry-Perot double-edge filter, then measurement capability is improved, but receiver efficiency decreases and system complexity increases
Solution Approach 1:
The patent extracts the wavelength selection function from complex filter-based systems (Fizeau spectrometer with Fabry-Perot double-edge filters) and implements it through simpler wavelength-selective optics. This extraction maintains the ability to measure both molecular and aerosol returns while significantly improving receiver efficiency by reducing the number of optical filters and interfaces.
3Measurement precision
If hybrid lidar systems use multiple lasers and receivers, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses a single laser source capable of emitting multiple wavelengths (355 nm for molecular scattering and 532 nm for aerosol scattering) and a single receiver with wavelength-selective detection. This universal system maintains wind speed measurement precision for both aerosol and molecular returns while dramatically reducing manufacturing costs by eliminating the need for multiple lasers, receivers, and associated optical components.
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 allows for efficient and cost-effective remote measurement of wind speeds by simplifying the system design and improving sensitivity, enabling simultaneous measurement of aerosol and molecular returns with reduced complexity and cost.
Implementation Method 1
an unequal path length interferometer with multiple optical path length differences... the interferometer includes first and second arms each having different optical path lengths... After light from the interferometer arms is recombined the interferometer additionally includes a first plurality of detectors configured to measure the intensity of the interference pattern formed by light of the first wavelength
Implementation Method 2
The first arm of the unequal path length interferometer includes a first reflective element or set of reflective elements that present a first optical path length to light of a first wavelength... and a second reflective element or set of reflective elements that present a second optical path length to light of a second wavelength
Data Source
AI summary
Lidar systems and methods are provided. The lidar system includes a laser that outputs light at two different wavelengths and an interferometer that is capable of generating fringe patterns for each of the two wavelengths simultaneously. More particularly, a first arm of the interferometer provides first and second path lengths. Light of a first of two or more wavelengths traverses the first path length within the first arm, while light of a second one of the two wavelengths traverses the second path length within the first arm. A second arm of the interferometer provides a third path length. Light from the first and second arms is then combined, and a phase shift of light of the first wavelength and a phase shift of light of the second wavelength are determined.