Epoxy-Filled Optical Coupler for Vertical Signal Routing
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Solution Overview
Problem
Optical couplers face challenges with physical warpage in devices with increasing aspect ratios, leading to optical coupling penalties, and grating couplers are limited by narrow spectral bandwidth and polarization sensitivity.
Innovation Solution
An optical coupler design featuring an interlayer dielectric with a cavity filled with epoxy, where the epoxy directs optical signals vertically using refractive index matching or a higher index than the dielectric, enabling wide spectral bandwidth and avoiding grating coupler limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grating couplers are used to provide vertical optical coupling, then optical coupling penalties from surface warpage are avoided, but spectral bandwidth becomes narrow and polarization sensitivity increases
Solution Approach 1:
The patent changes the refractive index parameter of the epoxy material to be higher than that of the interlayer dielectric, creating a refractive index contrast that enables total internal reflection at the epoxy-dielectric interface. This parameter change allows the epoxy to act as a waveguide that directs light vertically without requiring grating couplers, thereby achieving wide spectral bandwidth while maintaining coupling stability.
2Productivity
If devices with increasing aspect ratios are used, then integration density improves, but physical warpage of device surfaces occurs leading to optical coupling penalties
Solution Approach 1:
The patent replaces mechanical edge coupling methods with an optical waveguide-based vertical coupling system. By substituting the mechanical alignment approach with an optical field confinement approach using total internal reflection in the epoxy waveguide, the system becomes immune to surface warpage effects, maintaining coupling efficiency despite device warpage.
3Ease of manufacture
If edge coupling methods are used, then manufacturing is simpler, but sensitivity to surface warpage and alignment precision requirements increase
Solution Approach 1:
The patent introduces an intermediary epoxy waveguide layer between the optical component and the output medium. This intermediary structure performs two functions: it confines and directs the optical field vertically through total internal reflection, and it provides a refractive index transition that enables efficient coupling. This intermediary approach simplifies manufacturing while reducing sensitivity to alignment precision requirements.
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 design provides vertical optical coupling with increased spectral bandwidth and reduced sensitivity to surface warpage, eliminating edge coupling issues and maintaining efficiency across a broader range of wavelengths.
Implementation Method 1
The epoxy directs the optical signal from the first surface to the second surface
Implementation Method 2
epoxy directs an optical signal traveling laterally in the cavity towards a surface of the cavity that redirects the optical signal upwards
Data Source
AI summary
An optical coupler and a method performed by the optical coupler are described. The optical coupler includes an interlayer dielectric, a waveguide disposed within the interlayer dielectric, and an epoxy disposed on the interlayer dielectric and in the first cavity such that the epoxy defines an upper surface and a bottom surface. The interlayer dielectric includes a first surface and a second surface coupled to the first surface. The first surface and the second surface define a first cavity in the interlayer dielectric. The waveguide emits an optical signal through the first surface. The bottom surface is positioned between the interlayer dielectric and the upper surface. The epoxy directs the optical signal from the first surface to the second surface. The second surface and the epoxy direct a first portion of the optical signal through the upper surface.