Freeform Optical Couplers With Interposer Alignment for Dense Photonics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical couplers for interfacing on-chip waveguides with off-chip optical media face limitations such as low integration density, stringent optical alignment requirements, and sensitivity to polarization and fabrication accuracy, making them unsuitable for high-density, high-bandwidth applications in data centers and computing systems.
Innovation Solution
The development of a photonic interposer with free-form optical couplers and mechanical alignment structures, which includes a transparent substrate with polymer layers and optical couplers extending from both sides, allowing for precise alignment and efficient light coupling between optical fibers and photonic chips, even at the wafer scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If butt coupling is used to interface on-chip waveguides with off-chip optical media, then optical coupling efficiency can be achieved, but integration density is limited by chip edge length and stringent optical alignment requirements increase device complexity
Solution Approach 1:
The patent introduces a photonic interposer as an intermediary component between the photonic chip and optical fiber. The interposer includes a transparent substrate with free-form optical couplers (metasurfaces) that mediate the coupling process, eliminating the need for direct butt coupling alignment. The mechanical alignment structures on the interposer mate with complementary structures on the chip to provide robust positioning without requiring sub-micron alignment precision between the chip facet and optical fiber.
2Productivity
If grating couplers are used for optical coupling, then integration density can be improved, but spectral bandwidth is limited and polarization sensitivity increases device complexity
Solution Approach 1:
The patent employs free-form optical couplers with metasurfaces that can be designed with spatially varying parameters (refractive index, thickness, geometry) to control the phase, amplitude, and polarization of transmitted light. This allows the couplers to achieve broadband operation across multiple wavelengths and support both TE and TM polarizations simultaneously, overcoming the narrow bandwidth and polarization sensitivity limitations of grating couplers.
3Reliability
If precise active alignment is performed during assembly to achieve high coupling efficiency, then optical coupling performance is improved, but manufacturing time increases
Solution Approach 1:
The patent incorporates mechanical alignment structures (such as alignment keys, recesses, or interlocking features) that are pre-formed on both the photonic chip and the photonic interposer during fabrication. These pre-formed structures automatically guide and constrain the relative positioning of the chip and interposer during assembly, eliminating the need for time-consuming active alignment procedures and enabling rapid, repeatable assembly with consistent coupling performance.
4Productivity
If wafer-scale fabrication is used to improve manufacturing efficiency, then productivity is improved, but testing and characterization can only be performed at chip level after dicing
Solution Approach 1:
The photonic interposer is designed with universal mechanical alignment structures and optical coupling interfaces that work across the entire wafer scale. The transparent substrate with free-form optical couplers can be fabricated using wafer-scale processes, and the interposer itself serves as a test vehicle that allows optical characterization to be performed on multiple chiplets simultaneously before dicing, enabling wafer-level testing and screening capability.
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 solution enables high-performance optical coupling with low insertion loss and improved spectral bandwidth, overcoming the limitations of traditional couplers by providing flexible, efficient, and scalable integration of optical components.
Implementation Method 1
The free-form optical coupler extends from the first side of the transparent substrate and is configured to couple light through the transparent substrate
Data Source
AI summary
The present technology is related to optics and optical systems, particularly to photonic packaging, optical coupling, optical interconnects, micro-optics, and their fabrication. The present technology includes free-form micro-optical coupler architectures and systems with superb optical performance and a high-throughput method of fabricating large-area coupler arrays for scalable manufacturing. Embodiments include chip-to-fiber-array, chip-to-chip, chip-to-interposer, and chip-to-free-space couplers for applications including photonic packaging, optical communications, LiDAR, optical trapping and manipulation, augmented reality, virtual reality, and sensing.