Coherent Aperture Steering With Phase Imaging for Wide Field of Regard
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Solution Overview
Problem
Existing optical phased array systems face challenges in achieving both a large field of regard and long range due to limitations in aperture size and emitter distribution, with microscale systems providing high FOR but limited power and macroscopic systems sacrificing FOR for increased range.
Innovation Solution
A coherent aperture array system using physically steerable emitters that independently steer portions of the source beam, combined with a phase imaging system to ensure phase coherence, allowing for mechanically steered elements to suppress divergence and achieve large FOR while maintaining long range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If microscale optical phased arrays with tightly packed emitters are used, then field of regard is improved, but aperture size and beam range deteriorate
Solution Approach 1:
The system segments the aperture into multiple independently steerable emitter groups, where each group can be individually positioned and oriented. This allows the aperture to be distributed over a large area while maintaining the ability to steer beams independently, resolving the contradiction between large aperture size and large field of regard.
Solution Approach 2:
The invention transitions from a two-dimensional planar array to a three-dimensional distributed aperture configuration. Emitters are positioned at multiple spatial locations and orientations in 3D space, enabling both large effective aperture and wide field of regard by utilizing the additional spatial dimension.
2Area of stationary object
If macroscopic optical phased arrays with fewer emitters are used, then aperture size and beam range are improved, but field of regard deteriorates
Solution Approach 1:
The large macroscopic aperture is segmented into multiple steerable emitter groups that can independently adjust their orientation. This segmentation allows each subset of emitters to contribute to different angular sectors, collectively providing wide field of regard while maintaining the large total aperture area.
Solution Approach 2:
The system introduces dynamic steering capability to each emitter group, allowing real-time adjustment of beam directions. This dynamic control enables the fixed large aperture to adapt its effective viewing angle, achieving wide field of regard without sacrificing aperture size.
3Ease of operation
If mechanically steered emitters are used, then beam steering agility and field of regard are improved, but system complexity increases
Solution Approach 1:
The invention merges the steering functions of multiple emitters into a coordinated system controlled by a single processor. The processor calculates and applies phase adjustments to all emitters simultaneously, combining individual mechanical steering capabilities into a unified electronic control system that reduces operational complexity.
Solution Approach 2:
The system implements feedback control where the processor monitors the positions and orientations of steerable emitters and dynamically adjusts phase delays to maintain coherent beam formation. This feedback mechanism automates the complexity of coordinating multiple mechanical steers, simplifying operation while maintaining precision.
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 system enables large FOR and long-range optical beam steering with suppressed diffraction modes, effectively utilizing mechanically steered emitters to enhance beam quality and precision, suitable for applications like space-based laser communications.
Implementation Method 1
the phase imaging system measures optical path length to each steerable emitter to within one tenth of the source wavelength
Implementation Method 2
Each steerable emitter is further steerable such that the separate portions of the source beam projected from each steerable emitter coherently recombine to produce a coherent beam at a target location
Implementation Method 3
mechanically steered elements to suppress divergence and achieve large FOR while maintaining long range
Data Source
AI summary
A coherent aperture array system is used for steering an optical source beam. The system has spaced apart, steerable emitters each able to be mechanically aimed at a remote target location to steer portions of the source beam toward the target location. Each steerable emitter has a subaperture controllable independently of a remaining reflective surface of its associated steerable emitter, to receive and reflect a subportion of the source beam portion. The subportion forms a sense beam which is reflected toward a phase imaging system. A separate reference beam is created from the portion of the source beam travelling toward each steerable emitter. Each sense beam and each reference beam are thus associated uniquely with one of the steerable emitters. A phase imaging system uses the reference beams and the sense beams to determine phase differences between the portions of the source beam being transmitted from each steerable emitter.