On-Chip Optical Phased Array Serial Grating Antenna Design
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Solution Overview
Problem
Conventional on-chip optical phased arrays face challenges in reducing the spacing between antenna units due to the limitations of directional couplers, leading to increased device size and power consumption, while also struggling to form complex two-dimensional beam patterns efficiently.
Innovation Solution
The design employs an array of photonic grating antennas and phase shifters connected in series by photonic waveguides, arranged in a two-dimensional array, eliminating the need for directional couplers and waveguide splitters, allowing for reduced spacing between antennas and improved power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If directional couplers are used to distribute light in conventional designs, then light distribution capability is improved, but device size and power consumption increase significantly
Solution Approach 1:
The patent removes the directional coupler component entirely from the system. Instead of using directional couplers to distribute light, the invention uses a serial grating antenna configuration where each grating antenna directly couples to the waveguide, eliminating the need for separate light distribution components and significantly reducing device footprint.
Solution Approach 2:
The patent combines the light distribution function with the grating antenna structure itself. The grating antennas serve dual purposes: they act as both the radiating elements and the light coupling structures, merging what were previously separate components (directional coupler and antenna) into a single integrated structure.
2Ease of manufacture
If directional couplers are used to distribute light, then light distribution capability is improved, but power consumption increases due to more I/O ports and control circuits
Solution Approach 1:
By removing the directional coupler component, the patent eliminates the associated I/O ports and control circuits that would be required to manage multiple light distribution paths. This reduction in components directly translates to lower power consumption for control and monitoring.
Solution Approach 2:
The patent segments the light distribution function into individual grating antenna units that can be independently controlled, replacing the need for a centralized directional coupler system. This segmentation reduces the overall complexity and power requirements of the system.
3Ease of manufacture
If antenna spacing is increased due to directional coupler length limitations, then manufacturing is simplified, but side lobes in output beam increase
Solution Approach 1:
Instead of increasing antenna spacing to simplify manufacturing, the patent inverts the approach by reducing antenna spacing through the elimination of directional couplers. The serial grating antenna design allows antennas to be placed closer together, and the grating structure itself provides the necessary phase control to suppress side lobes.
Solution Approach 2:
The patent changes the critical parameter of antenna spacing by removing the constraint imposed by directional coupler length. This allows the spacing to be optimized for performance (closer spacing to reduce side lobes) rather than being limited by manufacturing constraints of existing components.
4Area of stationary object
If number of antennas is increased to reduce directional coupler size, then device footprint is reduced, but electronic control circuits and I/O ports become more complex
Solution Approach 1:
The patent segments the phased array into independent grating antenna units, each with its own phase control mechanism. This modular segmentation allows for reduced device footprint while keeping individual unit complexity manageable, as each unit operates independently rather than requiring complex inter-unit control circuits.
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 significantly reduces the overall size and cost of the phased array, minimizes side lobes in output beams, and enables the formation of complex optical patterns with improved power efficiency and reduced power consumption.
Implementation Method 1
an array of photonic antenna units which can produce complex still and scanning optical patterns through optical interference effect
Implementation Method 2
a phase shifter that can be used for adjusting the optical phase of each optical beam output to form certain optical interference arrangement
Implementation Method 3
a grating antenna, formed in an optical wave guiding layer, configured to emit a pre-defined portion of an input light out of a plane of the optical wave guiding layer
Data Source
AI summary
An on-chip optical phased array includes an array of photonic antenna units connected in series by photonic waveguides and arranged in a two-dimensional array to produce complex still and scanning optical patterns through optical interference effect. Each antenna unit includes an output photonic antenna (e.g. grating antenna), and a waveguide phase shifter for adjusting the optical phase of the optical beam output by the antenna unit. The grating antenna and the waveguide phase shifter are formed in the same optical wave guiding layer which includes a core layer between two cladding layers. The grating antennas may be a shallow-etched structure or a deep-etched edge-modulated grating. The optical phased array, including the array of photonic antenna units and the electrodes that connect and provide electrical power to them, can be made on a single chip of silicon using complementary metal-oxide-semiconductor (CMOS) or compatible fabrication processes.