Serpentine Optical Phased Array Dispersion Matching
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Solution Overview
Problem
Existing 2D optical phased array (OPA) systems face challenges in achieving high antenna density and large scanning cone due to the need for phase-shifters and bulky waveguide structures, which limit transverse steering capabilities and increase footprint.
Innovation Solution
A wavelength-based 2D OPA architecture using a serpentine arrangement of slow light waveguides with alternating dispersion slopes, eliminating the need for phase-shifters and non-radiating return waveguides, allowing for dense packing and efficient steering in both longitudinal and transverse directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase-shifters are used to control beam steering in 2D OPA, then transverse steering capability is improved, but device footprint and complexity increase
Solution Approach 1:
The patent removes phase-shifters entirely from the 2D OPA system and replaces them with a wavelength-based steering mechanism using a tunable laser source. This extraction of the phase-shifting function eliminates the associated footprint and complexity while maintaining transverse steering capability through spectral control of the light source.
Solution Approach 2:
The patent replaces the mechanical/electrical phase-shifting components with an optical wavelength-tuning mechanism. By controlling the wavelength of the laser source, the system achieves beam steering without requiring physical phase-shifters, thereby reducing device footprint while preserving steering functionality.
2Stability of the object's composition
If antenna spacing is reduced to less than half wavelength to avoid multiple lobes, then beam quality is improved, but phase-shifter size makes this difficult to achieve
Solution Approach 1:
The patent changes the operating parameter from fixed-frequency phase control to wavelength-tunable operation. By varying the wavelength of the laser source, the system can achieve the required phase differences for proper beam formation even with reduced antenna spacing, making it easier to manufacture compact arrays with single-lobe radiation patterns.
3Device complexity
If arrayed waveguide gratings are used for wavelength-based 2D steering, then phase control is simplified, but waveguide length and device area increase significantly
Solution Approach 1:
The patent extracts and eliminates the arrayed waveguide grating structure entirely, replacing it with a simpler wavelength-tunable laser source combined with direct waveguide coupling. This removal of the AWG eliminates the need for long delay waveguides while maintaining wavelength-based steering functionality, dramatically reducing the device area.
4Quantity of substance
If serpentine waveguide arrangement is used to increase antenna density, then transverse steering is improved, but non-radiating return waveguides limit the scanning cone
Solution Approach 1:
The patent removes the non-radiating return waveguides from the serpentine arrangement by using a different architecture where all waveguides are directly coupled to the laser source. This extraction eliminates the scanning cone limitation while preserving the high antenna density achieved through the compact waveguide layout.
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 design achieves higher antenna density and a larger 2D scanning cone with reduced footprint, enabling efficient beam steering in both directions without the limitations of previous OPA architectures.
Implementation Method 1
dispersion slopes of opposite sign and the same group index
Implementation Method 2
optical slow light waveguides arranged parallel to each other
Implementation Method 3
coherently combine to produce a beam
Data Source
AI summary
A dispersion-engineered 2D optical phased array device includes optical slow light waveguides [202, 208, 218] arranged parallel to each other; waveguide bends [206, 216] optically coupling ends of adjacent waveguides of the optical slow light waveguides to form a serpentine optical configuration; wherein the optical slow light waveguides comprise first waveguides of a first waveguide type and second waveguides of a second waveguide type, wherein the first waveguides and the second waveguides are arranged adjacent to each other and alternate with each other; wherein the optical slow light waveguides comprise phased array sections forming a phased array [214], wherein first waveguides and second waveguides have dispersion slopes of opposite sign and the same group index; wherein the optical slow light waveguides comprise slow light delay waveguide sections [210] that provide a delay between adjacent waveguides.