Coherent Multi-Beam Optical Phased Array for Low-Loss RF Beamforming
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Solution Overview
Problem
Existing electronic-based beamforming architectures for mmWave communications face challenges such as high insertion loss, complex control, and limited scalability in massive MIMO systems, particularly in hybrid beamforming architectures.
Innovation Solution
A coherent optical phased array using phase change materials (PCM) phase shifters and a novel crossbar architecture with passive couplers and waveguide crossings, enabling independent beam control and reduced control complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electronic-based beamforming architectures are used for mmWave communications, then beamforming capability is achieved, but insertion loss increases and scalability is limited
Solution Approach 1:
The patent replaces electronic-based beamforming with an optical-based beamforming system. Optical signals are used to control the phase and amplitude of RF signals across antenna elements, substituting electronic control mechanisms with optical control mechanisms. This substitution reduces insertion loss because optical signals experience minimal attenuation in waveguide structures, and enables scalability to massive MIMO systems with hundreds or thousands of antenna elements.
Solution Approach 2:
The patent introduces optical signals as an intermediary between the control system and the antenna elements. Instead of directly controlling RF signals electronically, the system uses optical signals to modulate and control the RF beamforming. The optical signals serve as a low-loss transmission medium for control information, enabling precise phase and amplitude control across large antenna arrays without the insertion loss problems of electronic systems.
2Reliability
If hybrid beamforming architectures are used, then beamforming performance is improved, but control complexity increases
Solution Approach 1:
The patent replaces complex electronic control circuits with optical control mechanisms. Instead of using multiple electronic phase shifters and amplitude controllers that require complex coordination, the system uses optical signals to simultaneously control multiple antenna elements. The optical-based approach simplifies the control architecture by using light as the control medium, which can carry multiple channels of control information with minimal interference, thereby reducing control complexity while maintaining beamforming performance.
3Productivity
If large antenna arrays are deployed for massive MIMO, then capacity is increased, but power consumption increases
Solution Approach 1:
The patent replaces power-hungry electronic control circuits with low-power optical control mechanisms. In electronic beamforming systems, each antenna element typically requires its own phase shifter and amplitude controller, leading to linearly increasing power consumption with the number of elements. The optical-based system uses a single optical source that can control all antenna elements through optical distribution, dramatically reducing the total power consumption while enabling massive MIMO deployments with hundreds or thousands of elements to increase system capacity.
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 low insertion loss, low power consumption, and scalable beam steering capabilities, suitable for large antenna arrays, with reduced control complexity and improved performance in mmWave and terahertz frequency bands.
Implementation Method 1
an optical signal source generating an optical signal; a first set of waveguides connected to the optical signal source and configured to propagate the optical signal
Implementation Method 2
a phase shifter coupled to each of the splitters, each of the phase shifters being controllable to modify a shift in a phase of the optical signal received from a corresponding splitter
Implementation Method 3
a photodetectors coupled to each waveguide of the second set of waveguides and configured to receive a heterodyne optical signal from the waveguide and generate a corresponding electrical signal
Implementation Method 4
a coupler connected to each of the phase shifters and to one waveguide of the second set of waveguides for introducing the optical signal after shifting
Data Source
AI summary
A coherent multi-beam optical phased array for radio-frequency beamforming is provided. The optical phase array includes an optical signal source generating an optical signal, a first set of waveguides connected to the optical signal source and configured to propagate the optical signal, a second set of waveguides, a set of splitters along each of the first set of waveguides configured to split the optical signal, a phase shifter coupled to each of the splitters, each phase shifter being controllable to modify a phase shift of the optical signal, a coupler connected to each of the phase shifters and to one waveguide of the second set of waveguides for introducing the optical signal after shifting, and a photodetector coupled to each waveguide of the second set of waveguides and configured to receive a heterodyne optical signal from the waveguide and generate a corresponding electrical signal.