MEMS Vertical Coupler Array for Fast Low-Loss Beam Steering
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Solution Overview
Problem
Existing beam-steering technologies for free-space optical communications and LiDAR are bulky, heavy, power-consuming, and have limited frequency response, making them unsuitable for fast-moving applications, while electronic and thermo-optic switches face scalability and temperature sensitivity issues.
Innovation Solution
A programmable, integrated-optics-based 2D array of mechanically active vertical-grating couplers, monolithically integrated on a substrate, with a switching network that controls which coupler is energized, mitigating optical crosstalk and enabling efficient beam steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If motorized mechanical gimbals are used to rotate the entire optical system, then beam steering function is achieved, but the system becomes bulky, heavy, and power-consuming
Solution Approach 1:
The patent replaces motorized mechanical gimbals with a MEMS-based optical switching system. Instead of physically rotating heavy optical components, the invention uses microelectromechanical switches to redirect light paths through an array of vertical couplers, achieving beam steering without moving the entire optical system. This substitution eliminates motors, gears, and heavy mechanical structures while maintaining steering functionality.
Solution Approach 2:
The optical system is divided into multiple independent vertical coupler elements arranged in an array. Each coupler can be independently controlled by MEMS switches to direct light in different directions. This segmentation allows the system to achieve beam steering by selectively activating individual elements rather than moving the entire system, reducing weight and complexity.
2Ease of operation
If mechanical systems are used to move the lens and/or light source, then beam steering is achieved, but the frequency response is limited due to weight/stiffness
Solution Approach 1:
The patent replaces heavy mechanical moving systems with MEMS-based optical switching. The MEMS switches have minimal moving mass compared to mechanical lens or light source positioning systems, enabling much faster switching speeds and higher frequency response. The optical paths are redirected through fixed optical elements rather than moving them, achieving fast beam steering suitable for LiDAR and communications.
Solution Approach 2:
The system transitions from static mechanical positioning to dynamic optical switching. The MEMS-controlled vertical coupler array enables rapid, programmable beam steering by electrically controlling which coupler elements are active, allowing for high-speed beam direction changes without mechanical inertia limitations.
3Ease of operation
If electronic crossbar switches with VCSEL arrays are used, then beam steering is achieved, but large arrays of lasers are required and VCSEL sources are not well suited for some applications
Solution Approach 1:
The patent uses a single input light source that serves all beam steering functions through the vertical coupler array. Instead of requiring multiple VCSEL elements, one light source is distributed to multiple output directions via the MEMS-controlled couplers. This multi-functional approach eliminates the need for large arrays of laser sources while maintaining the ability to steer beams in multiple directions.
Solution Approach 2:
The vertical coupler array acts as an intermediary between a single light source and multiple beam directions. The couplers, controlled by MEMS switches, distribute the single input light to different output paths, replacing the need for multiple direct laser sources. This intermediary structure simplifies the system while achieving the same functional result.
4Ease of operation
If silicon-photonic-based thermo-optic switches are used, then beam steering is achieved, but temperature sensitivity, limited steering capability, high power consumption and poor scalability occur
Solution Approach 1:
The patent replaces thermo-optic switching with MEMS-based mechanical optical switching. Instead of using heat to change refractive indices for beam steering, the invention uses microelectromechanical actuators to physically position optical elements. This mechanical approach consumes significantly less power than thermal control while providing comparable or superior steering capability and eliminating temperature sensitivity issues.
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 provides agile, high-resolution beam steering with low optical loss and power consumption, suitable for LiDAR, optical communications, and medical imaging, and can steer multiple beams simultaneously.
Implementation Method 1
each coupler of the array thereof including a coupler waveguide and a vertical-coupling element that is configured to launch optical energy received from the coupler waveguide into free space
Implementation Method 2
The lens is arranged to convert free-space light emitted by any of the couplers into a collimated, free-space light beam
Data Source
AI summary
An integrated-optics MEMS-actuated beam-steering system is disclosed, wherein the beam-steering system includes a lens and a programmable vertical coupler array having a switching network and an array of vertical couplers, where the switching network can energize of the vertical couplers such that it efficiently emits the light into free-space. The lens collimates the light received from the energized vertical coupler and directs the output beam along a propagation direction determined by the position of the energized vertical coupler within the vertical-coupler array. In some embodiments, the vertical coupler is configured to correct an aberration of the lens. In some embodiments, more than one vertical coupler can be energized to enable steering of multiple output beams. In some embodiments, the switching network is non-blocking.