Molded Optical Interposer Coupler for PIC Polarization Control
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Solution Overview
Problem
Efficient coupling of light between individual optical elements in single mode optical systems is challenging due to the need for accurate spatial and angular alignment, polarization management, and isolation from back-reflections, which are not adequately addressed by current assembly technologies, leading to high costs and complexity in high-priced applications.
Innovation Solution
A glass-molded interposer with integrated polarization selective elements, such as gratings or thin-film coatings, facilitates low-cost optical coupling and polarization management, enabling efficient coupling and isolation by using high-precision glass-molding technology and wafer-scale assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If discrete optical elements are assembled using conventional assembly technologies, then optical coupling can be achieved, but alignment accuracy and polarization management are insufficient, leading to high costs and complexity
Solution Approach 1:
The patent combines multiple discrete optical elements (lenses, polarization selective elements, isolators) into a single integrated optical assembly. This merging eliminates the need for separate alignment procedures for each component, thereby improving alignment accuracy while reducing assembly complexity. The integrated design allows all elements to be positioned relative to each other in a single manufacturing process rather than through multiple sequential alignment steps.
Solution Approach 2:
The patent introduces a specialized substrate or mounting structure that serves as an intermediary platform for positioning optical elements. This intermediary structure incorporates features such as precision-machined mounting surfaces, alignment marks, and integrated polarization selective coatings that facilitate accurate positioning without requiring complex external alignment equipment or procedures.
2Loss of energy
If accurate spatial and angular alignment is implemented for single mode optical coupling, then coupling efficiency improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent implements preliminary alignment features during the manufacturing process, such as pre-positioned mounting structures, pre-applied polarization selective coatings, and pre-integrated isolator elements. These preliminary actions ensure that when the optical assembly is assembled, the components are already in their correct spatial and angular positions, minimizing coupling loss without requiring complex post-assembly alignment procedures.
Solution Approach 2:
The patent optimizes key parameters such as lens focal lengths, element spacing, and angular orientations to achieve optimal coupling efficiency. By carefully selecting and adjusting these parameters during the design and manufacturing stages, the system achieves low coupling loss while maintaining ease of manufacture through standardized component specifications and simplified assembly procedures.
3Reliability
If polarization selective elements are added to manage polarization, then polarization control improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent integrates polarization selective elements directly onto the substrate or mounting structure rather than assembling them as separate components. This merging approach combines polarization control functionality with the mechanical support structure, thereby improving polarization control reliability while reducing the overall number of discrete components and simplifying the optical system architecture.
Solution Approach 2:
The substrate or mounting structure serves multiple functions: it provides mechanical support for optical elements, establishes precise spatial and angular relationships between components, and incorporates polarization selective coatings or elements. This multi-functionality reduces device complexity by eliminating the need for separate polarization control components while maintaining reliable polarization management.
4Reliability
If isolators are implemented with discrete components to prevent back-reflections, then laser stability improves, but assembly complexity and manufacturing cost increase
Solution Approach 1:
The patent integrates isolator elements directly into the optical assembly on the same substrate as other optical components. This merging eliminates the need for separate assembly steps for isolators and ensures that the isolators are precisely positioned relative to the laser and other elements, thereby maintaining laser stability while simplifying manufacturing and assembly procedures.
Solution Approach 2:
The substrate serves as an intermediary that positions the isolator elements in their correct locations and orientations relative to the laser and other optical components. This intermediary structure ensures proper isolation functionality while simplifying assembly, as the isolators are already positioned correctly during substrate fabrication rather than requiring separate alignment procedures.
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 provides low-loss optical coupling with integrated polarization management and isolation, reducing manufacturing costs and complexity while maintaining high performance, suitable for high-bandwidth optical interconnects in data centers.
Implementation Method 1
a polarization selective reflector or polarization selective filter implemented with treatment of an internal or external surface
Implementation Method 2
polarization selective reflector
Implementation Method 3
glass-molded interposer with integrated polarization selective elements
Data Source
AI summary
The invention describes an apparatus that implements efficient coupling between a photonic integrated circuit (PIC) and a second optical element such as a fiber or laser, while at the same time allowing for efficient polarization management and/or optical isolation. It enables the packaging of PICs with large single mode fiber counts and in- and out-coupling of light with arbitrary polarization. The apparatus comprises a glass interposer that contains at least one polarization selective element together with a pair of lenses transforming a beam profile between the 2nd optical element and a polarization selective coupler on the PIC. The invention also comprises a method for fabricating the apparatus based on a subassembly of building blocks that are manufactured using wafer-scale high-precision glass-molding and surface treatment(s) such as thin-film coating.