Multimode Interferometer Acute Angle Geometry Stray Light Reduction
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Solution Overview
Problem
Mach-Zehnder modulators face performance degradation due to stray light produced by multimode interferometers, which affects the extinction ratio and overall optical device efficiency.
Innovation Solution
The design incorporates a multimode waveguide mesa with specific geometric features, such as acute angles at vertices, to refract light components away from the port, reducing stray light by reflecting and refracting light components back towards the waveguide mesa, thereby minimizing stray light propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multimode interferometer is used in a Mach-Zehnder modulator, then optical signal splitting and merging is achieved, but stray light is generated that degrades the extinction ratio and optical device efficiency
Solution Approach 1:
The patent extracts and removes the harmful stray light components from the optical path by designing the multimode waveguide mesa geometry to refract stray light away from the port, separating the useful optical signal from the harmful stray light
Solution Approach 2:
The patent applies asymmetry by designing the multimode waveguide mesa with specific geometric features including acute angles at vertices and non-symmetric side face inclinations, which cause stray light to be refracted in specific directions away from the port while allowing useful light to pass through
2Reliability
If the multimode waveguide mesa geometry is optimized to reduce stray light, then the extinction ratio improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent changes geometric parameters of the multimode waveguide mesa, specifically setting the acute angle at the vertex between the top face and side face within a specific range (15-45 degrees), and controlling the inclination angles of side faces, to optimize stray light reduction while maintaining manufacturability
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 effectively reduces stray light in Mach-Zehnder modulators, enhancing the extinction ratio and improving the optical modulation quality by minimizing unwanted light reflections.
Implementation Method 1
The design incorporates a multimode waveguide mesa with specific geometric features, such as acute angles at vertices, to refract light components away from the port
Implementation Method 2
reducing stray light by reflecting and refracting light components back towards the waveguide mesa
Data Source
AI summary
A multimode interferometer includes: a multimode waveguide mesa having a top face extending in a direction of a first axis, a first side face and a second side face that extend in the direction of the first axis, and a first end face and a second end face that are arranged in the direction of the first axis; and a waveguide mesa connected to the first end face at a port; first and second waveguide mesas connected to first and second ports on the second end face. The multimode waveguide mesa has a first side edge line shared by the top face and the first side face, and an end line shared by the top face and the first end face. The first side edge line forms an acute angle with the end line at an outer vertex where the first side edge line and the end line meet.