Optical Phased Array With Rayleigh Scatterers for Low-Loss Beam Steering
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Solution Overview
Problem
Existing optical phased arrays face challenges in achieving a large effective aperture size due to structural complexity and high optical loss, limiting lateral and angular resolution, and scalability, especially in LiDAR systems.
Innovation Solution
An optical phased array comprising a waveguide with Rayleigh scatterers having a diagonal or diameter of one-tenth the wavelength of the input optical field, enabling efficient beam steering and forming over a wide field-of-view using standard fabrication techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple meta-atoms are used for each repeating unit of emitters to induce additional optical phase shift, then beam directionality is enhanced, but optical loss in the waveguide increases substantially and fabrication complexity increases
Solution Approach 1:
The patent changes the size parameter of scatterers to be substantially smaller than the wavelength of light (sub-wavelength scatterers), which fundamentally alters the scattering regime from Mie scattering to Rayleigh scattering. This parameter change enables phase modulation with significantly reduced optical loss compared to using multiple larger meta-atoms, while still achieving the required beam directionality control.
Solution Approach 2:
The patent extracts the essential function of phase modulation from complex multi-atom meta-structures and implements it through simple sub-wavelength scatterers. By taking out only the necessary scattering function and removing the complex meta-atom structure, the patent achieves beam directionality enhancement with reduced optical loss and simplified fabrication.
2Measurement precision
If multiple meta-atoms are used for each repeating unit of emitters to induce additional optical phase shift, then beam directionality is enhanced, but fabrication complexity and assembly costs increase
Solution Approach 1:
The patent replaces expensive, complex meta-atom structures with simple, inexpensive sub-wavelength scatterers that can be fabricated using standard lithographic techniques. These simple scatterers are easier to manufacture and assemble, reducing both fabrication complexity and assembly costs while maintaining the necessary beam directionality control function.
Solution Approach 2:
The patent segments the phase modulation function into individual sub-wavelength scatterers distributed along the waveguide, rather than using clustered meta-atoms. This segmentation allows for simpler fabrication of each individual scatterer and easier assembly, while the collective effect of multiple scattered elements achieves the required beam directionality enhancement.
3Loss of energy
If sub-wavelength scatterers are used instead of meta-atoms, then optical loss is reduced and fabrication is simplified, but aperture size must be increased to maintain resolution
Solution Approach 1:
The patent uses preliminary action by implementing phase modulation through sub-wavelength scatterers before the light reaches the emission point. This preliminary phase control allows for more efficient use of the aperture, enabling reduced aperture size while maintaining resolution, because the phase information is encoded earlier in the propagation path with lower loss.
4Ease of manufacture
If standard CMOS-compatible fabrication processes are used, then manufacturing cost is reduced and scalability is improved, but control over complex meta-atom structures is limited
Solution Approach 1:
The patent changes the structural parameters of the scatterers to be sub-wavelength in size, which makes them compatible with standard lithographic fabrication processes. This parameter change allows standard CMOS-compatible processes to achieve the required manufacturing precision without needing specialized meta-atom fabrication techniques, thereby reducing cost and improving scalability.
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
The solution provides a low-cost, scalable, and efficient beam steering system with enhanced aperture size, improving lateral and angular resolution and reducing the impact of obscurants, suitable for LiDAR and transceiver applications.
Implementation Method 1
at least a waveguide and a plurality of scatterers, with each scatterer having a diagonal or diameter which is at most one-tenth the wavelength of the input optical field
Data Source
AI summary
An optical phased array comprises photonic components for on-chip beam forming and steering, and is adapted to use an input optical field of a beam having a wavelength which ranges from visible light to a short-wavelength infrared region. The photonic component comprises at least a waveguide and a plurality of scatterers, with each scatterer having a diagonal which is at most about one-tenth the wavelength of the input optical field.