Multi-Pixel Waveguide Optical Receiver for Destructive Interference
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Solution Overview
Problem
In lidar systems, the spatial phase variations of scattered light can lead to destructive interference when coupled into optical transmission media, resulting in loss of information and inaccurate measurements due to the varying spatial phase across the receiving area.
Innovation Solution
A multi-pixel waveguide optical receiver is employed, where each pixel is smaller than the expected optical speckle size, and a combiner is used to combine the optical fields from multiple pixels into a multimode waveguide, reducing destructive interference and preserving the received light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single large pixel receiver is used to collect reflected laser light, then the light collection area is maximized, but spatial phase variations across the receiving area cause destructive interference and information loss
Solution Approach 1:
The receiver is divided into multiple pixels, each smaller than the optical speckle size. This segmentation ensures that spatial phase variations are confined within each pixel, preventing destructive interference while collectively maintaining a large light collection area through the combined pixels.
2Loss of information
If multiple small pixels are used to avoid destructive interference, then information loss is reduced, but the overall light collection area decreases
Solution Approach 1:
Multiple pixels are combined into a single receiver assembly that collectively provides a large light collection area. The combiner integrates the optical fields from all pixels, merging their individual small collection areas into an effective large collection area while preserving the phase uniformity benefits of small pixels.
3Device complexity
If a single mode waveguide is used to transmit light from the receiver, then the device complexity is minimized, but destructive interference causes signal loss and measurement inaccuracies
Solution Approach 1:
The waveguide is designed to support multiple modes instead of a single mode. This parameter change in the waveguide's optical characteristics allows it to accommodate the optical fields from multiple pixels without destructive interference, thereby improving measurement accuracy while accepting increased 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
This configuration limits destructive interference, allowing for more accurate processing of electrical signals and improved measurement accuracy by ensuring that the spatial phase across each pixel remains substantially uniform, thus reducing signal loss and enhancing the quality of the received light.
Implementation Method 1
the receiver has multiple pixels having a size that is smaller than an expected optical speckle size, wherein the expected optical speckle size corresponds to a region on the receiver where the reflected laser light has a substantially uniform spatial phase
Implementation Method 2
a combiner configured to combine optical fields from each pixel in the multiple pixels into an output that supports a number of modes that is equal to a number of pixels in the multiple pixels
Implementation Method 3
a photodetector configured to receive light from the output
Data Source
AI summary
Systems and embodiments for a multi-pixel waveguide optical receiver are described herein. In certain embodiments, a system includes an emitter that emits laser light towards a surface. The system also includes a receiver that passively receives reflected laser light that is a portion of the laser light reflected from the surface, wherein the receiver has multiple pixels having a size that is smaller than an expected optical speckle size, wherein the expected optical speckle size corresponds to a region on the receiver where the reflected laser light has a substantially uniform spatial phase. Additionally, the system includes a combiner configured to combine optical fields from each pixel in the multiple pixels into an output that supports a number of modes that is equal to a number of pixels in the multiple pixels. Moreover, the system includes a photodetector configured to receive light from the output.