Optical-Phased Array Beam Steering via Wavelength Tuning
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Solution Overview
Problem
Existing solid-state optical-phased array (OPA) beam-steerers face challenges in scaling up for high-resolution beams and large field of view due to power consumption issues, thermal cross-talk, and the need for complex electronics, as well as limitations in wavelength scan and scanning granularity.
Innovation Solution
The implementation of a star coupler coupled with multiple grating couplers and optical delay lines, along with a tunable laser and optical switch, allows for a compact and scalable OPA design that achieves a Gaussian power distribution and efficient beam steering across a wide field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active phase-shifters are used to compensate for manufacturing phase errors and control beam steering, then beam steering precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts and removes the active phase-shifters from the optical phased array system, replacing them with a passive grating coupler array that achieves beam steering through wavelength tuning alone, thereby eliminating the complexity and power consumption associated with active phase-control electronics
Solution Approach 2:
The patent replaces the electronic phase-control system with an optical wavelength-tuning system, where beam steering is achieved by tuning the laser wavelength rather than electronically controlling phase-shifters, substituting a mechanical/optical approach for an electronic one
2Measurement precision
If active phase-shifters are used for beam steering control, then beam steering precision is improved, but power consumption increases
Solution Approach 1:
The patent removes the power-consuming active phase-shifters from the system, achieving beam steering through passive grating couplers controlled by wavelength-tuned lasers, thereby eliminating the continuous power consumption required by electronic phase-control circuits
Solution Approach 2:
The patent uses periodic wavelength sweeping of the laser to achieve beam steering across multiple directions, replacing the continuous power consumption of active phase-shifters with intermittent wavelength tuning that consumes less energy
3Device complexity
If single-input slab coupler OPA is used, then device complexity is reduced, but scanning granularity and field of view are limited
Solution Approach 1:
The patent segments the optical system into multiple independent grating couplers arranged in an array, each capable of receiving light at different wavelengths to steer beams in different directions, thereby achieving fine scanning granularity without increasing overall device complexity
Solution Approach 2:
The patent adds the wavelength dimension to the beam steering control, using wavelength-multiplexed grating couplers to achieve 2D scanning capability (both angular and spectral dimensions) without increasing the physical footprint or complexity of the optical path
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 enables efficient beam steering with reduced power consumption and thermal issues, allowing for scalable and high-resolution beam steering with improved scanning granularity and wavelength scan capabilities, suitable for applications like automotive lidar.
Implementation Method 1
a plurality of grating couplers... steering the light from the plurality of grating couplers according to a desired scanning pattern
Implementation Method 2
each output of the star coupler is coupled to a grating coupler of the plurality of grating couplers via an optical delay line of a plurality of optical delay lines, wherein the optical delay line is an optical waveguide
Data Source
AI summary
An aspect of the disclosure provides for an optical-phased array (OPA) comprising a star coupler coupled to a plurality of grating couplers, wherein the star coupler comprises multiple inputs and multiple outputs. In some embodiments, each output of the star coupler is coupled to a grating coupler of the plurality of grating couplers. In some embodiments, the star coupler is coupled to the plurality of grating couplers by a plurality of optical delay lines. In some embodiments each output of the star coupler is coupled to a grating coupler of the plurality of grating couplers via an optical delay line of the plurality of optical delay lines. In some embodiments, the OPA further includes an optical switch coupled to the multiple inputs of the star coupler, and at least one tunable laser. Another aspect of the disclosure provides a method for steering light using the OPA.