VCSEL Arrays with Holographic Diffusers for Free-Space Optical Links
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current high power semiconductor laser transmitters and optical modulators are cost-prohibitive for short distance optical communications, and existing VCSEL arrays fail to achieve the necessary high bandwidth and power for efficient free space optical communications, especially due to alignment and mechanical complexity issues.
Innovation Solution
The development of high power VCSEL arrays with flexible design configurations, such as sub-arrays and multiple wavelength arrays, that allow for non-mechanical alignment and increased power density, enabling high-speed and cost-effective optical wireless communications by leveraging holographic optical diffusing elements and beam spreading techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high power semiconductor laser transmitters and optical modulators are used to achieve high bandwidth, then bandwidth is improved, but cost becomes prohibitive
Solution Approach 1:
The patent segments the optical transmitter into multiple independent VCSEL elements arranged in arrays, where each element can be independently controlled. This segmentation allows the system to achieve high aggregate bandwidth through parallel operation of multiple lower-cost VCSELs rather than relying on expensive single high-power laser transmitters with optical modulators
Solution Approach 2:
The patent replaces mechanical alignment systems with optical field-based alignment using holographic optical elements. The holographic diffusing elements create expanded optical fields that are inherently more tolerant of misalignment, eliminating the need for complex mechanical positioning mechanisms and reducing overall system cost while maintaining high bandwidth performance
2Ease of manufacture
If VCSEL arrays are used to increase power and reduce cost, then cost is reduced, but bandwidth is insufficient
Solution Approach 1:
The patent merges multiple VCSEL elements into unified arrays that operate in parallel, combining their individual bandwidth contributions to achieve aggregate bandwidth levels comparable to or exceeding traditional high-power laser systems. The holographic optical elements merge the optical fields from multiple VCSELs into a coordinated transmission pattern, enabling cost-effective high-bandwidth communication
Solution Approach 2:
The patent transitions from single-element to multi-element array configurations, adding spatial dimensionality to the transmission system. By arranging VCSELs in two-dimensional arrays with independent control, the system achieves bandwidth scaling through spatial parallelism rather than relying on the temporal modulation limits of single high-power lasers
3Productivity
If traditional laser transmitters are used to achieve high bandwidth, then bandwidth is improved, but alignment complexity increases
Solution Approach 1:
The patent introduces holographic optical diffusing elements as intermediaries between the VCSEL arrays and the transmission medium. These elements serve as optical mediators that transform the coherent beams from individual VCSELs into expanded, diffuse optical fields that are inherently more tolerant of alignment errors, simplifying the alignment process while maintaining high bandwidth capability
Solution Approach 2:
The patent changes the optical field parameters by using holographic elements to transform narrow, coherent laser beams into expanded, diffuse fields with larger angular spread. This parameter transformation increases the effective aperture and tolerance to misalignment, reducing alignment complexity while preserving the high bandwidth achieved through parallel VCSEL operation
4Manufacturing precision
If mechanical alignment components are used to achieve precise alignment, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent substitutes mechanical alignment components with optical field-based alignment using holographic diffusing elements. Instead of using mechanically assembled components to achieve alignment, the system uses the inherent properties of expanded optical fields to provide alignment tolerance, eliminating complex mechanical connectors and positioning mechanisms while maintaining manufacturing precision
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 approach enables unprecedented bandwidth levels at a reasonable cost, reduces cabling complexity, and enhances reliability by overcoming alignment challenges, making high-speed optical communications feasible between adjacent circuit boards and in data centers with improved power efficiency and reduced mechanical complexity.
Implementation Method 1
transmit a string of binary data through the air or other free space using a laser
Implementation Method 2
leveraging holographic optical diffusing elements and beam spreading techniques
Data Source
AI summary
High power, high speed VCSEL arrays are employed in unique configurations of arrays and sub-arrays. Placement of a VCSEL array behind a lens allows spatial separation and directivity. Diffusion may be employed to increase alignment tolerance. Intensity modulation may be performed by operating groups of VCSEL emitters at maximum bias. Optical communications networks with high bandwidth may employ angular, spatial, and/or wavelength multiplexing. A variety of network topologies and bandwidths suitable for the data center may be implemented. Eye safe networks may employ VCSEL emitters may be paired with optical elements to reduce optical power density to eye safe levels.