Multimode Interference Device Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multimode interference devices with MMI semiconductor mesas embedded in resin bodies exhibit unexpected deviations in branching ratios, leading to performance degradation beyond design tolerance, particularly in 2×2 MMI structures.
Innovation Solution
The implementation of a multimode interference device with an MMI semiconductor mesa embedded in an embedding region, where first and second semiconductor mesas are disposed apart from the MMI semiconductor mesa's side faces, and metal bodies make contact through openings in the embedding region, forming stack structures that restrict the embedding region's extent and reduce stress on the MMI semiconductor mesa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an MMI semiconductor mesa is embedded in a resin body, then the device structure is formed and supported, but stress is applied to the MMI semiconductor mesa causing deviation in branching ratios
Solution Approach 1:
The device is segmented into three separate semiconductor mesas (first semiconductor mesa, MMI semiconductor mesa, second semiconductor mesa) instead of a single integrated structure. This segmentation isolates the MMI semiconductor mesa from direct stress transmission through the resin body, as each mesa is independently supported. The first and second semiconductor mesas act as separate structural elements that do not directly transfer stress to the MMI mesa, thereby reducing stress-induced branching ratio deviations.
Solution Approach 2:
The resin body acts as an intermediary material that fills the spaces between the first semiconductor mesa, MMI semiconductor mesa, and second semiconductor mesa. This intermediary resin layer provides mechanical support and structural integrity while isolating the MMI semiconductor mesa from direct stress applied to the other mesas. The openings in the resin body allow metal bodies to contact the first and second semiconductor mesas without directly stressing the MMI semiconductor mesa.
2Strength
If the embedding region covers the MMI semiconductor mesa extensively, then structural support is provided, but stress-induced refractive index unevenness increases
Solution Approach 1:
The embedding structure is designed with local quality differentiation: the resin body covers the side faces of all three semiconductor mesas for structural support, but specifically excludes the top surface of the MMI semiconductor mesa through openings. This allows the resin to provide mechanical strength and support where needed (side faces) while avoiding areas where stress would affect optical performance (top surface of MMI mesa). The first and second semiconductor mesas have openings allowing metal contact, creating localized stress relief zones.
3Ease of manufacture
If metal bodies contact the first and second semiconductor mesas through openings, then electrical connection is achieved, but the embedding region structure is complicated
Solution Approach 1:
The metal bodies are extracted from the embedding region by creating openings through the resin body. Instead of embedding metal contacts within the resin matrix, the design removes material (creates openings) to allow direct contact between metal bodies and the first/second semiconductor mesas. This simplifies the electrical connection process while maintaining a relatively simple embedding region structure, as the resin body still provides comprehensive coverage and support.
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 reduces deviations in light branching ratios, enhancing the performance of the multimode interference device and integrated Mach-Zehnder modulation devices by minimizing stress-induced refractive index unevenness and maintaining desired branching ratios.
Implementation Method 1
the multimode interferometer enables multiple interference to divide light incident on one input port among the input ports into the multiple output ports
Data Source
AI summary
A multimode interference device includes: man MMI semiconductor mesa having first and second end faces that are arranged in a direction of a first axis, and first and second side faces that extend in the direction of the first axis; first and second semiconductor mesas disposed apart from the first and second side faces, respectively; an embedding region covering the MMI semiconductor mesa and the first and second semiconductor mesas and having first and second openings at the first and second semiconductor mess, respectively; and first and second metal bodies making contact with the first and second semiconductor mesas through the first and second openings, respectively. The first and second end faces have multiple first ports and multiple second ports, respectively. The first semiconductor mesa, the MMI semiconductor mesa, and the second semiconductor mesa are arranged in a direction of a second axis intersecting the first axis.