Rib-Type Optical Waveguide Intersection Design
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Solution Overview
Problem
In optical communication and interconnect systems, existing technologies fail to adequately reduce signal loss and polarization dependency at intersection points of optical waveguides, leading to inefficiencies as integration scales increase, and do not effectively manage diffracted light.
Innovation Solution
An optical circuit element with a rib-type waveguide structure featuring intersection points aligned on a straight line, where the core width between points is wider than elsewhere, and interconnected by a taper waveguide, with a thicker slab in regions with wider core widths to minimize loss and polarization dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the core width is enlarged at the intersection point to reduce diffraction loss, then the signal loss is reduced, but the device complexity and manufacturing difficulty increase due to the need for taper portions and precise width control
Solution Approach 1:
The patent applies local quality by varying the core width at specific locations: the core width is enlarged at the intersection point (wider than standard regions) to reduce diffraction loss, while maintaining standard width in other regions. This localized modification targets the specific problem area without unnecessarily complicating the entire waveguide structure.
Solution Approach 2:
The patent uses tapered portions with gradual width transitions instead of abrupt changes. The core width changes continuously through the taper portions connecting the wider intersection region to standard width regions, reducing reflections and manufacturing difficulty compared to sharp transitions.
2Reliability
If multiple intersection points are disposed on a straight line to improve alignment and reduce polarization dependency, then the polarization dependency is reduced, but the signal loss increases due to cumulative diffraction effects
Solution Approach 1:
The patent changes the core width parameter at the intersection points (making them wider) to reduce diffraction loss. By adjusting this physical parameter, the patent achieves better transmission characteristics while maintaining the straight-line arrangement of multiple intersection points for polarization independence.
3Loss of energy
If the core width is uniformly enlarged throughout the waveguide to minimize diffraction, then the diffraction loss is reduced, but the manufacturing precision requirements and device complexity increase significantly
Solution Approach 1:
Instead of uniformly enlarging the core width throughout the entire waveguide, the patent applies local quality by enlarging the core width only at the intersection points where diffraction occurs. The standard width is maintained in non-intersection regions, reducing manufacturing complexity while targeting the specific areas needing diffraction mitigation.
Solution Approach 2:
The patent uses tapered portions with gradual width transitions to connect the wider intersection regions with standard width regions. This continuous transition avoids abrupt changes, reducing reflections and simplifying manufacturing compared to sharp transitions, while still achieving the desired diffraction reduction.
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 configuration enables low-loss, low-polarization-dependent optical signal transmission by controlling higher modes and reducing inter-mode interference, effectively addressing the limitations of previous technologies.
Implementation Method 1
by using silicon as a core and silica as a cladding and exploiting a high refractive index difference between the core and the cladding
Implementation Method 2
it is difficult to avoid occurrence of diffraction in an optical signal propagating through an optical waveguide
Data Source
AI summary
In order to solve the problem of making optical signals pass at a low loss and low polarization dependence, this optical circuit element is configured from rib-type optical waveguides, each of which is configured from a core region, including a planar slab and protruding ribs, and cladding regions that are provided in contact with the top and the bottom of the core region. A first optical waveguide that is provided in the optical circuit element is provided with a plurality of intersection points where the first optical waveguide intersects optical waveguides other than the first optical waveguide, said intersection points being disposed on one straight line. The core width of the first optical waveguide in a region between the intersection points is larger than the core width of the first optical waveguide in regions other than the region between the intersection points, the first optical waveguide regions having different core widths are connected by means of a taper optical waveguide wherein the core width monotonously changes, and the thickness of the slab of the first optical waveguide in the region having the large core width is larger than the thickness of the slab of the first optical waveguide in the regions other than the region having the large core width.