Hybrid MCM Waveguide-Fiber Connector Alignment
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Solution Overview
Problem
Current silicon-photonics technologies face challenges in developing efficient laser sources due to silicon's poor light emission properties and integration issues with III-V compound semiconductors, leading to low optical-waveguide-coupled efficiency and high costs in hybrid laser production.
Innovation Solution
A multi-chip module (MCM) incorporating an interposer, a photonic chip with a silicon-on-insulator technology, an optical gain chip with a III-V compound semiconductor, and a waveguide-fiber connector, enabling low-cost co-planar integration and high-precision alignment for efficient optical signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If edge-to-edge butt-coupling of III-V compound-semiconductor optical gain medium with silicon optical waveguides is used, then high electrical injection efficiency and low thermal impedance are maintained, but optical-mode mismatch requires special mode size converters and sub-micron alignment tolerances which decrease yield and increase cost
Solution Approach 1:
The patent introduces an intermediary component (mode size converter or adapter) that mediates between the III-V compound-semiconductor optical gain medium and silicon optical waveguides. This intermediary element transforms the optical mode size to match between the two different materials, eliminating the need for sub-micron alignment tolerances and special mode size converters on both sides, thereby reducing manufacturing cost while maintaining high electrical injection efficiency.
Solution Approach 2:
The patent segments the hybrid laser system into distinct functional modules: the III-V compound-semiconductor optical gain medium, the mode size converter/adapter, and the silicon optical waveguides. This segmentation allows each component to be independently optimized and fabricated, then assembled with relaxed alignment tolerances, improving yield and reducing cost while preserving the high electrical injection efficiency of the III-V material.
2Manufacturing precision
If edge-to-edge butt-coupling with sub-micron alignment tolerances is required, then efficient optical coupling is achieved, but yield decreases and cost increases
Solution Approach 1:
The patent employs an intermediary mode size converter or adapter that acts as a buffer between the optical components. This intermediary element provides mechanical alignment features with relaxed tolerances (greater than sub-micron) while maintaining efficient optical coupling through its designed mode-matching geometry, thereby significantly improving production yield without sacrificing alignment precision.
Solution Approach 2:
The patent changes the alignment tolerance parameter from sub-micron to relaxed tolerances by introducing the mode size converter/adapter. This parameter change is achieved by designing the intermediary component with specific geometric parameters that provide both mechanical alignment features with relaxed tolerances and efficient optical mode matching, thereby increasing productivity and yield.
3Reliability
If wafer bonding of III-V compound semiconductors to silicon is performed, then hybrid lasers are successfully demonstrated, but optical-waveguide-coupled overall efficiency is reduced due to taper loss, carrier-injection efficiency, and thermal impedance
Solution Approach 1:
The patent introduces an intermediary mode size converter or adapter between the III-V compound-semiconductor optical gain medium and silicon optical waveguides. This intermediary element provides optimized optical mode matching that reduces taper loss and improves carrier-injection efficiency, thereby increasing optical-waveguide-coupled overall efficiency while maintaining hybrid laser functionality through wafer bonding.
4Adaptability or versatility
If III-V compound-semiconductor wafers are bonded to silicon wafers, then hybrid integration is achieved, but optical-mode mismatch between the two materials requires special mode size converters
Solution Approach 1:
The patent merges the mode size conversion function with the wafer bonding interface by designing an integrated mode size converter/adapter that combines both functions in a single component. This merging eliminates the need for separate mode size converters on both sides of the bond interface, reducing device complexity while maintaining hybrid integration capability between III-V compound-semiconductor and silicon wafers.
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 MCM achieves high-efficiency, compact, and scalable chip-to-chip and board-to-board optical interconnects with low power consumption, overcoming integration and alignment challenges in hybrid laser production.
Implementation Method 1
an optical waveguide defined in the BOX layer and the semiconductor layer
Implementation Method 2
the waveguide-fiber connector includes a third optical waveguide that optically couples the first end and the second end
Data Source
AI summary
A multi-chip module (MCM) includes: an interposer, a photonic chip, an optical gain chip, and a waveguide-fiber connector. The photonic chip, which may be electrically coupled to the interposer, may be implemented using a silicon-on-insulator (SOI) technology, and may include an optical waveguide that conveys an optical signal. Moreover, the optical gain chip, which may be electrically coupled to the interposer, may include a III-V compound semiconductor, and may include a second optical waveguide that conveys the optical signal and that is vertically aligned with the optical waveguide relative to a top surface of the interposer. Furthermore, the waveguide-fiber connector may be mechanically coupled to the interposer, and remateably mechanically coupled to an optical fiber coupler that includes the optical fiber. The waveguide-fiber connector may convey the optical signal between the optical waveguide in the photonic chip and the optical fiber.