Optical Phased Array Beam Control with Shared Grating
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Solution Overview
Problem
Optical phased arrays (OPAs) operating in the micron-scale wavelength range face challenges with large grating sizes leading to coupling crosstalk and reduced emission angles, affecting scanning output efficiency and efficiency.
Innovation Solution
A beam controller with an optical phased array, free-space beam combining area, and shared grating transmitter, where sub-beams are combined in a fan shape and diffracted independently, allowing for larger beam emission angles and reduced grating side lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a weak grating is used to emit the beam transmitted by the waveguide perpendicular to the surface of the waveguide over a longer distance, then the divergence angle of the beam is reduced, but the spacing between adjacent second-order linear gratings becomes small, leading to coupling crosstalk between corresponding parallel-arranged waveguides
Solution Approach 1:
The patent divides the beam transmission system into two independent parts: waveguide transmission (for combining beams) and grating transmission (for emitting beams). By separating these functions spatially and functionally, the grating spacing can be optimized for emission without being constrained by waveguide coupling requirements, thus reducing crosstalk while maintaining long transmission distance
Solution Approach 2:
The patent introduces a beam combining area as an intermediary region where multiple waveguide beams are combined into a single beam before reaching the grating. This intermediary structure allows the grating to receive consolidated light flux, enabling larger grating spacing and reducing coupling crosstalk between adjacent waveguides
2Manufacturing precision
If the spacing between adjacent second-order linear gratings is reduced to prevent grating side lobes, then beam scanning quality is improved, but the emission angle is decreased and scanning output efficiency is lowered
Solution Approach 1:
The patent separates the beam combining function (performed by waveguides in the beam combining area) from the beam emission function (performed by the grating). This segmentation allows the grating to be designed independently with optimized spacing for emission angle, while the waveguide array handles the beam combining and side lobe control separately
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional free-space beam combining approach. By allowing beams to propagate in free space and combine at an image plane, the system achieves better control over beam combining without constraining the grating spacing, thus improving emission angle while maintaining scanning output efficiency
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
Enhances scan output efficiency and emission angle while minimizing grating side lobes, improving overall optical performance.
Implementation Method 1
The beam splitter is configured to: equally split an initial light beam into a plurality of sub-beams
Implementation Method 2
The waveguides are configured to receive and transmit the sub-beams
Implementation Method 3
the combination of the plurality of sub-beams is completed by free focusing in the free-space beam combining area
Implementation Method 4
the emission of the corresponding combined light beam is completed by diffraction performed by the shared grating transmitter
Data Source
AI summary
A beam controller and a beam controlling method are provided. The beam controller comprises an optical phased array including a beam splitter and a waveguide array coupled to the beam splitter, a free-space beam combining area, and a shared grating transmitter. The beam splitter is configured to equally split an initial light beam into a plurality of sub-beams. The waveguide array comprises a plurality of waveguides arranged in one-to-one correspondence to the sub-beams. The waveguides are configured to receive and transmit the sub-beams. Transmission tail sections of the plurality of waveguides are concentrated in the free-space beam combining area in a fan shape manner. The free-space beam combining area is configured to enable the plurality of sub-beams to be combined on an image plane. The shared grating transmitter is configured to diffract and transmit a combined light beam that the plurality of sub-beams are combined on the image plane.