Mirrored Facet Mach-Zehnder Interferometer Compact Footprint
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Solution Overview
Problem
Conventional Mach-Zehnder interferometers (MZIs) with delay lines have a large footprint, making them unsuitable for compact applications and requiring multiple substrates for manufacturing, which increases complexity and costs, and often necessitate undesirable waveguide crossings.
Innovation Solution
The design incorporates mirrored facets within the chip, allowing the delay line and non-delay line arms to have equal optical path lengths, eliminating the need for additional optical transmission elements and enabling independent, compact configurations without waveguide crossings, by reflecting portions of the optical beam back to the optical transmission element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional delay line MZI design is used with longer delay line arm, then optical path length difference is achieved for time delay, but device footprint becomes large
Solution Approach 1:
The patent introduces a vertical dimension by fabricating waveguides at different depths within the substrate. The first waveguide is formed at a first depth while the second waveguide is formed at a second depth greater than the first depth. This three-dimensional arrangement allows the optical paths to be stacked vertically, achieving the required time delay through depth differentiation rather than horizontal extension, thereby reducing the device footprint while maintaining the necessary optical path length difference.
2Loss of time
If delay line arm is made longer to achieve time delay, then optical path length difference is obtained, but manufacturing complexity increases requiring multiple substrates
Solution Approach 1:
The patent introduces a vertical dimension by fabricating waveguides at different depths within the substrate. The first waveguide is formed at a first depth while the second waveguide is formed at a second depth greater than the first depth. This three-dimensional arrangement allows the optical paths to be stacked vertically, achieving the required time delay through depth differentiation rather than horizontal extension, thereby reducing the device footprint while maintaining the necessary optical path length difference.
Solution Approach 2:
The patent embeds one optical path within the substrate at a different depth level than the other optical path. The second waveguide is formed at a greater depth than the first waveguide, creating a nested three-dimensional structure where optical paths are contained within different layers of the same substrate. This nesting approach integrates multiple optical paths into a single substrate volume, eliminating the need for multiple separate substrates and reducing manufacturing complexity.
3Ease of operation
If conventional MZI design is used, then optical signal splitting and combining is achieved, but waveguide crossings are required
Solution Approach 1:
The patent introduces a vertical dimension by fabricating waveguides at different depths within the substrate. The first waveguide is formed at a first depth while the second waveguide is formed at a second depth greater than the first depth. This three-dimensional arrangement allows the optical paths to be stacked vertically, achieving the required time delay through depth differentiation rather than horizontal extension, thereby reducing the device footprint while maintaining the necessary optical path length difference.
Solution Approach 2:
The patent segments the optical paths into distinct three-dimensional regions by forming waveguides at different depths. The first optical path is confined to a first depth region while the second optical path is confined to a second depth region. This spatial segmentation separates the optical paths vertically, eliminating the need for horizontal waveguide crossings and simplifying the overall device structure.
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 reduces the MZI footprint by half or more, enabling compact designs suitable for applications like LIDAR, and allows multiple MZIs to be formed on a single substrate, simplifying manufacturing and assembly while avoiding waveguide crossings.
Implementation Method 1
the mirrored facet configured to reflect, to the delay line arm, a percentage of the light propagated to the mirrored facet by the delay line arm
Data Source
AI summary
In some implementations, a Mach-Zehnder interferometer (MZI) includes a delay line arm formed in a chip and a mirrored facet formed in the chip. The delay line arm may be configured to propagate light to the mirrored facet. The mirrored facet may be configured to reflect, to the delay line arm, a percentage of the light propagated to the mirrored facet by the delay line arm.