Grating Switch Emitter Array for Phase-Accurate Beam Steering
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Solution Overview
Problem
Conventional silicon photonics enabled optical phased arrays face challenges in accurately controlling the phase of wavelength branches due to environmental impacts like temperature drift, leading to unintended phase shifts that compromise beam quality and accuracy in optical sensing systems, particularly in autonomous navigation applications.
Innovation Solution
An emitter array with a plurality of waveguide branches integrated with grating switches that can selectively turn on or off to control light emission, eliminating the need for phase shifting elements by using an upper grating structure to couple with the waveguide branch and allow light to exit through diffraction, enabling precise beam steering without power-intensive thermal or electro-optical tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal phase shifting elements are used to correct phase shift, then phase accuracy is improved, but power consumption increases significantly
Solution Approach 1:
The patent removes phase shifting elements entirely from the system. Instead of adding components to correct phase errors, the invention uses a grating coupler approach where light is coupled out of the waveguide at a specific angle determined by the grating equation, eliminating the need for thermal or electro-optical phase shifters and their associated power consumption
Solution Approach 2:
The patent replaces the thermal mechanical phase shifting mechanism with a static grating coupler structure. The grating provides fixed angular beam steering without requiring active thermal control, substituting a passive optical structure for an active thermal control system
2Adaptability or versatility
If thermal phase shifting elements are used to steer the beam, then beam steering capability is improved, but the system response time decreases due to thermal time constants
Solution Approach 1:
The patent extracts the beam steering function from the thermal phase shifting mechanism and implements it through electronic control of grating coupler activation. This allows instantaneous beam direction changes limited only by the electronic control speed, not by thermal response time
Solution Approach 2:
The patent introduces dynamic control through electronic switching of the grating coupler activation state. The system can rapidly transition between different beam steering states by controlling which waveguide branches are active, enabling fast response times suitable for real-time autonomous navigation
3Measurement precision
If electro-optical phase shifting elements are used to tune phase, then phase control precision is improved, but integration with waveguide branches becomes difficult and costly
Solution Approach 1:
The patent removes electro-optical phase shifting elements from the system and replaces them with a grating coupler-based approach. This eliminates the integration challenges and high fabrication costs associated with incorporating electro-optical materials into silicon photonics waveguides
Solution Approach 2:
The patent changes the operating principle from active phase tuning to passive angular coupling. By using the grating equation to determine beam direction based on coupling angle rather than phase shifting, the system achieves beam steering without requiring complex electro-optical integration
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 solution enhances the accuracy and efficiency of beam steering in optical sensing systems by reducing power consumption and integration complexity, while maintaining high resolution and range, thus improving navigation and sensing capabilities in environments prone to temperature variations.
Implementation Method 1
an upper grating structure configured to couple to a waveguide branch when the grating switch is activated to allow the light to emit from the waveguide branch
Data Source
AI summary
Embodiments of the disclosure provide an emitter array for an optical sensing system. The emitter array may include a waveguide including a plurality of waveguide branches. The emitter array may also include a plurality of grating switches positioned along each of the plurality of waveguide branches and configured to selectively turn on or off the corresponding waveguide branch for transmitting light. In certain aspects, a grating switch may include an upper grating structure configured to couple to a waveguide branch when the grating switch is activated to allow the light to emit from the waveguide branch.