Optical Interposer Using Diffraction Grating Couplers for VCSEL Arrays
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Solution Overview
Problem
Existing solutions for coupling single mode Vertical-Cavity Surface-Emitting Lasers (VCSELs) to optical fibers suffer from low efficiency and high optical losses due to surface-normal perpendicular coupling, limiting the scalability and density of VCSEL arrays.
Innovation Solution
An optical interposer using first order diffraction grating couplers to refract light from single mode VCSELs at an angle of at least 4 degrees, coupled with optical waveguides and output ports to interface with standard fiber arrays, enhancing coupling efficiency and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If surface-normal perpendicular coupling is used to couple VCSEL light into waveguides, then the coupling structure is simple, but substantial optical losses occur
Solution Approach 1:
The patent changes the coupling angle parameter from perpendicular (90 degrees) to oblique angles (45-60 degrees), and modifies the grating structure parameters to achieve constructive interference at these angles, thereby reducing optical losses while maintaining manufacturing feasibility
Solution Approach 2:
The patent introduces a lateral dimension to the coupling by using oblique angle incidence instead of perpendicular coupling, and employs diffraction gratings that operate in multiple dimensions to redirect light efficiently into waveguides
2Quantity of substance
If VCSEL array density is increased, then more laser sources are available for parallel fiber architectures, but coupling efficiency decreases due to surface-normal perpendicular coupling
Solution Approach 1:
The patent changes the coupling geometry parameters to oblique angles and modifies the grating period and depth parameters to optimize coupling efficiency for high-density arrays, enabling dense VCSEL packaging without proportional increases in loss
Solution Approach 2:
The patent divides the coupling function into separate components: diffraction gratings for angle conversion and waveguides for light transport, allowing each to be optimized independently for high-density array applications
3Ease of manufacture
If multi-mode VCSELs are used, then coupling into waveguides is easier, but power consumption increases excessively
Solution Approach 1:
The patent modifies the coupling parameters (angle, grating structure) to work efficiently with single-mode VCSELs, achieving adequate coupling efficiency without requiring multi-mode operation, thereby maintaining low power consumption
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
The solution achieves higher reproducibility and density of single mode VCSEL arrays with reduced optical coupling losses, enabling more efficient and cost-effective integration with standard fiber arrays, while minimizing thermal mismatch issues and power consumption.
Implementation Method 1
an array of first order diffraction grating couplers arranged to couple light emitted by an array of single mode Vertical-Cavity Surface-Emitting Lasers (VCSELs) into optical waveguides
Implementation Method 2
a device for refracting the light over an angle of at least 4 degrees from the substantially perpendicular direction wherein the light is emitted
Data Source
Figure 1a
Figure 1b~1c
Figure 2~3
AI summary
An optical interposer (100) comprising an array of first order diffraction grating couplers (104) arranged to couple light emitted by an array of single mode VCSELs (121) into optical waveguides (103), the light being emitted in a direction substantially perpendicular to the optical waveguides (103); a device (130) for refracting the light over at least 4 degrees; an array of output ports (102) arranged to optically couple light from the optical waveguides (103) into an array of optical fibers or other optical elements; and the optical waveguides (103) connecting the array of first order diffraction grating couplers (104) and the array of output ports (102) to route the light from the diffraction gratings (104) into the output ports (102).