End-Fire Taper Emitter Array for LIDAR Beam Steering
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Solution Overview
Problem
Conventional LIDAR systems face challenges such as high power consumption, limited beam steering capabilities, complex beamforming algorithms, and fabrication non-uniformity, particularly with grating couplers used in silicon photonics, which are inefficient, wavelength-dependent, and unable to implement low-loss monostatic systems leveraging polarization.
Innovation Solution
An optical emitter device featuring a two-dimensional array of point emitters with end-fire tapers and turning reflectors, arranged on a chip near the focal plane of a lens system, allowing for efficient beam steering without requiring precise phase control between emitters, enabling uniform broadband transmission across all polarization states and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grating couplers are used as point emitters in silicon photonics, then beam steering can be achieved, but emission efficiency is poor and fabrication uniformity is limited
Solution Approach 1:
The patent changes the emitter type from grating couplers to end-fire tapers, fundamentally altering the emission mechanism. End-fire tapers provide broad bandwidth and high efficiency by guiding light along the waveguide axis and coupling it to free space, eliminating the wavelength dependence and efficiency limitations of grating couplers
Solution Approach 2:
The patent replaces the grating-based diffraction mechanism with a direct end-fire coupling mechanism. This substitution eliminates the need for complex grating structures and their associated fabrication tolerances, achieving superior emission efficiency and broadband performance
2Ease of operation
If conventional phased-array methods are used for beam steering, then beam direction can be controlled, but power consumption is high due to phase control requirements
Solution Approach 1:
The patent extracts and eliminates the phase control subsystem from the beam steering mechanism. By using end-fire tapers with inherent directional emission and adding simple reflectors, the system removes the need for complex phase modulators and control electronics, dramatically reducing power consumption while maintaining two-dimensional steering capability
Solution Approach 2:
The end-fire taper structure inherently provides directional beam emission based on its geometric orientation. The system leverages this self-directed emission property, requiring no external phase control, making the beam steering passive and energy-efficient
3Ease of operation
If grating couplers are used for emission, then beam direction can be controlled, but the system shows strong wavelength dependence
Solution Approach 1:
The patent changes the emission mechanism from grating-based diffraction to end-fire direct coupling. End-fire tapers are inherently broadband because they rely on geometric coupling rather than wavelength-specific diffraction conditions, enabling the system to operate across a wide wavelength range without performance degradation
4Productivity
If conventional emitter arrays are used, then beam steering is possible, but fabrication process uniformity is difficult to achieve
Solution Approach 1:
The patent replaces complex grating structures requiring precise fabrication with simple end-fire taper waveguides. The taper geometry is much more tolerant to fabrication variations, and the addition of reflective surfaces provides a straightforward method to achieve the desired beam direction without stringent fabrication requirements
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, low-power, two-dimensional beam steering with improved fabrication uniformity and polarization independence, enhancing the performance and cost-effectiveness of LIDAR systems by eliminating the need for complex phase control and leveraging the advantages of end-fire tapers and turning reflectors.
Implementation Method 1
one of a plurality of end-fire tapers configured to emit a respective beam of light in a respective transmission direction
Implementation Method 2
a plurality of reflectors for redirecting the respective beams of light substantially perpendicular to the respective transmission direction
Data Source
AI summary
In an optical emitter device, when point emitters are placed on the focal plane of a lens system, each individual point emitter will point to a specific free space angle depending on the position of the point emitter relative to the longitudinal central axis of the lens system. Point emitters comprising end-fire tapers combined with both a turning mirror and a micro-lens provide improved performance, because, unlike grating couplers, end-fire tapers enable uniform broadband operation with all possible polarization states. A turning mirror may be added to direct the light emission from the end-fire tapers to vertically upwards, which enables both a two-dimensional point emitter array and a more streamlined assembly process.