MEMS Micro-Mirror Array Piston Steering for Diffraction Control
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Solution Overview
Problem
Conventional optical beam steering methods, such as waveguides and gimbal systems, face limitations in cost, weight, speed, and wavelength versatility, particularly in small angle steering applications, where diffraction issues and material specificity hinder efficient beam steering and imaging.
Innovation Solution
A Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) with piston capability is used to minimize diffraction by partitioning mirrors into sections that can tip, tilt, and translate to approximate a continuous surface, allowing for efficient small angle optical beam steering across various wavelengths without material changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a waveguide such as liquid crystal waveguide (LCWG) is used to steer beam, then cost and weight are reduced, but steering range, speed, and wavelength versatility are limited
Solution Approach 1:
The system divides the optical beam steering task into multiple wavelength-specific subsystems, each handling a particular wavelength band. This segmentation allows each subsystem to be optimized for its specific wavelength range while maintaining overall system versatility across multiple wavelengths.
Solution Approach 2:
The patent implements a universal beam steering platform that can handle multiple wavelengths by integrating multiple waveguide subsystems with different material compositions. Each waveguide is tailored for specific wavelength ranges, but collectively they provide broad spectral coverage, achieving multi-functionality without requiring complete system redesign for each wavelength.
2Ease of operation
If a gimbal system is used to position beamforming optics, then mechanical scanning capability is achieved, but cost and weight significantly increase
Solution Approach 1:
The patent replaces traditional mechanical gimbal systems with electrically controlled waveguide-based beam steering. Instead of physically moving heavy optical components via gimbals, the system uses electrical signals to control the orientation and steering of optical beams through waveguide arrays, eliminating the need for large mechanical scanning structures while maintaining scanning capability.
3Weight of stationary object
If waveguide solution is used for beam steering, then cost and weight are reduced, but diffraction effects and wavefront distortion increase
Solution Approach 1:
The patent introduces phase correction elements and beam combining optics as intermediary components between the waveguide subsystems and the final output beam. These intermediaries compensate for diffraction effects and wavefront distortions introduced by individual waveguides, reconstructing a clean, coherent output beam that minimizes harmful diffraction patterns.
Solution Approach 2:
The system dynamically adjusts operational parameters such as waveguide excitation phases, amplitudes, and relative timing to optimize beam quality. By changing these parameters adaptively, the system compensates for diffraction effects and maintains high beam coherence across different steering angles and wavelength combinations.
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 reduces wavefront distortion and increases imaging resolution by minimizing diffraction effects, enabling faster and more versatile beam steering with reduced system weight and cost, suitable for applications like space-based systems and vibration stabilization.
Implementation Method 1
The MEMS MMA is positioned to receive the beam of optical radiation and tip, tilt and piston the mirrors to reflect and scan the beam over a portion of the scene within a field-of-view of the optical receiver
Implementation Method 2
Active optical systems use laser radiation to illuminate a scene
Data Source
AI summary
Small angle optical beam steering is performed using a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) that minimizes diffraction for a specified steering angle, Generally speaking, this is accomplished with a MEMS MMA that exhibits a “piston” capability to translate individual mirrors in addition to the tip and tilt capabilities. Adjacent mirrors can be tipped/tilted to the specified steering angle and then translated by a requisite amount to approximate a continuous surface. For a specified steering angle, the MEMS MMA is partitioned into one or more sections with each section including the maximum number of mirrors that can be grouped together and actuated to approximate a continuous surface given a maximum translation z. As a result, the only edge discontinuities exist between adjacent sections thereby minimizing distortion for a given steering angle.