LIDAR Spatial Beam Combining for Same-Wavelength Power Scaling
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Solution Overview
Problem
Combining laser light beams of the same wavelength from different sources presents challenges due to the need for wavelength separation, limiting the use of dichroic surfaces and restricting the number of beams that can be combined using polarization beam combining to two.
Innovation Solution
A steered LIDAR system with a transmit module that emits a scanning pulsed fanned laser beam, using polarization beam combining to combine multiple laser diodes' outputs, and an arrayed receiver to capture reflected light, allowing for increased emitted laser light power by adjusting the angular relationship and overlap of beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If dichroic surfaces are used to combine laser beams, then light power is increased, but wavelength separation is required which limits combining same-wavelength beams
Solution Approach 1:
The patent changes the parameter of beam combination from wavelength-based (dichroic) to spatial/angular-based (scanning mirror). By controlling the angular relationship between beams and using spatial overlap in the scanning path, same-wavelength beams can be combined without wavelength separation, resolving the contradiction between power increase and wavelength adaptability
Solution Approach 2:
The patent moves the combination mechanism from the wavelength dimension to the spatial/angular dimension. By using scanning mirrors to control beam angles and positions in space, beams of the same wavelength can be combined through spatial overlap during scanning, eliminating the wavelength separation constraint while maintaining power increase
2Power
If polarization beam combining is used to combine same-wavelength beams, then light power is increased, but the number of beams that can be combined is limited to two
Solution Approach 1:
The patent segments the beam combination process into multiple stages using multiple scanning mirrors. Each mirror handles a subset of beams, and the combined output is further processed by subsequent mirrors. This segmentation allows more than two beams to be combined by distributing them across multiple combination stages, resolving the limitation of polarization beam combining
Solution Approach 2:
The patent merges multiple laser beams into a single scanning path using angular control. By adjusting the angular relationship between input beams and using spatial overlap in the scanning trajectory, multiple beams are combined into one output beam, increasing emitted power without limiting the number of input beams
3Length of moving object
If multiple laser beams are combined to increase power, then range is improved, but beam control and spatial management become more complex
Solution Approach 1:
The scanning mirrors serve multiple functions: they scan the combined beam across the field of view, control the angular relationship between input beams, and manage spatial overlap of multiple beams. This multi-functionality reduces the need for separate control mechanisms for each beam, managing complexity while enabling range extension through power increase
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 the combination of multiple same-wavelength laser beams, increasing the emitted light power and range, while maintaining ambient light noise immunity and adaptive control of the field of view for improved scanning capabilities.
Implementation Method 1
Polarization beam combining is a technique that can combine same-wavelength light beams having different linear polarization states (S,P) using a polarizing beam splitter
Implementation Method 2
Combining laser light of different wavelengths from different sources can be readily achieved using dichroic surfaces
Implementation Method 3
A steered LIDAR system with a transmit module that emits a scanning pulsed fanned laser beam
Implementation Method 4
scanning LIDAR systems
Data Source
AI summary
A light detection and ranging system includes synchronously scanning transmit and receive mirrors that scan a pulsed fanned laser beam in two dimensions. Imaging optics image a receive aperture onto an arrayed receiver that includes a plurality of light sensitive devices. Scanning mirror offsets may be applied to modify a fan angle of the pulsed fanned laser beam. Adaptive methods dynamically modify the size and location of the field of view, laser pulse properties, and/or fan angle in response to internal and external sensors data.