PCSEL Arrays for Optical Neural Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser-based computing systems, particularly VCSELs, face limitations in scalability and energy efficiency due to large footprints, poor electron-photon and photon-photon interactions, and the need for external lasers for coherent locking, which restricts computational density and increases energy requirements.
Innovation Solution
The use of photonic crystal surface-emitting lasers (PCSELs) with smaller emitters and inherent coherent laser beam locking, eliminating the need for external lasers, allows for higher computational density and energy efficiency by enabling smaller separation of laser emitters and facilitating parallel operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VCSELs are used for laser-based computing, then coherent laser beam locking can be achieved, but external lasers are required which increases device complexity and energy consumption
Solution Approach 1:
PCSELs achieve self-coherence through their photonic crystal structure that provides inherent mode selection and phase locking without requiring external laser injection. The photonic crystal surface-emitting laser structure enables the device to lock its own coherent beam through internal feedback mechanisms, eliminating the need for external laser sources and reducing system complexity.
Solution Approach 2:
The patent extracts and removes the external laser component from the system by implementing coherent beam locking directly within the PCSEL structure itself. This extraction of the external laser requirement simplifies the overall system architecture while maintaining the essential coherent beam locking functionality.
2Power
If VCSELs are used for computing applications, then laser emission can be achieved, but large footprints limit scalability and computational density
Solution Approach 1:
The photonic crystal structure introduces local quality variations through periodic refractive index changes at the micrometer scale, enabling precise control of laser emission properties. This local structuring allows for compact emitter designs with reduced footprints while maintaining effective laser emission capability for computing applications.
Solution Approach 2:
The patent transitions from conventional three-dimensional laser cavity designs to a two-dimensional photonic crystal surface-emitting structure. This dimensional change enables lateral confinement of light through in-plane photonic bandgaps, allowing for smaller emitter footprints while maintaining effective laser emission for computing applications.
3Power
If VCSELs are used for optical computing, then beam emission can be achieved, but poor electron-photon and photon-photon interactions reduce energy efficiency
Solution Approach 1:
The patent employs composite material structures combining different semiconductor layers with distinct optical and electrical properties. This composite approach enhances electron-photon interaction through optimized carrier injection and recombination regions, while photonic crystal structures improve photon-photon interaction via strong optical confinement and enhanced light-matter coupling, thereby improving overall energy efficiency.
Solution Approach 2:
The patent optimizes energy efficiency by changing key parameters including the photonic crystal lattice constant, hole size and distribution, active region composition, and cavity depth. These parameter adjustments enhance the interaction between electrons and photons as well as between photons themselves, leading to improved energy efficiency in optical computing operations.
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
PCSELs overcome the limitations of VCSELs by providing improved scalability and energy efficiency, enabling higher computational speeds and densities without the need for external laser injection locking, thus enhancing the performance of optical neural networks and photonic computing.
Implementation Method 1
Each emitter is a photonic crystal surface-emitting laser (PCSEL) that emits a coherent beam
Implementation Method 2
a two-dimensional photonic crystal surface emitting laser (PCSEL) array including a plurality of PCSEL emitters
Implementation Method 3
a photodetector array located in a second layer comprised above the first layer
Data Source
AI summary
A laser-based computing system includes a two-dimensional photonic crystal surface emitting laser (PCSEL) array including a plurality of PCSEL emitters located in a first layer, each emitter oriented in a direction perpendicular to a plane formed by the first layer, where the plurality of PCSEL emitters form a preset pattern within the first layer, and a controller operatively connected to the plurality of PCSEL emitters, the controller configured to modulate phase and/or amplitude of a beam emitted by a PCSEL emitter of the plurality of PCSEL emitters.