Optical Coupler for Photonic Integrated Circuit Vertical Signal Routing
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Solution Overview
Problem
Current optical interconnects face challenges in achieving high accuracy and low-cost assembly due to tight fabrication tolerances and material requirements, particularly in coupling optical signals between photonic integrated circuits and optical fibers, leading to increased complexity and cost.
Innovation Solution
The use of a photonic integrated circuit (PIC) with a coupled waveguide assembly comprising low-index and high-index waveguides and reflective surfaces for efficient out-of-plane coupling, enabling precise alignment and mode conversion of optical signals, compatible with flip-chip assembly methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tight fabrication tolerances and strict material requirements are used for optical interconnects, then coupling accuracy between VCSELs and optical fibers is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent introduces an optical coupler as an intermediary component between the VCSEL and optical fiber. This coupler includes a substrate with a waveguide that receives optical signals from the VCSEL and directs them into the optical fiber. By placing this intermediate structure, the system achieves accurate coupling without requiring extremely tight fabrication tolerances on the direct VCSEL-to-fiber interface, thus reducing manufacturing complexity while maintaining coupling accuracy.
Solution Approach 2:
The optical interconnect is segmented into distinct functional components: the VCSEL, the optical coupler (with substrate and waveguide), and the optical fiber. This segmentation allows each component to be optimized and assembled separately, reducing the overall manufacturing complexity compared to a monolithic integrated structure requiring tight tolerances across all interfaces.
2Measurement precision
If tight fabrication tolerances are applied to optical interconnect components, then alignment accuracy between optoelectronic components is improved, but production cost increases
Solution Approach 1:
The optical coupler serves as a mediator that provides a stable reference frame for alignment. The substrate and waveguide structure define precise optical paths, allowing components to be aligned to the coupler rather than requiring direct alignment between VCSEL and fiber with extremely tight tolerances. This reduces production cost while maintaining alignment accuracy.
Solution Approach 2:
The patent changes the geometric parameters of the waveguide and coupling structure to optimize alignment tolerance. By designing the waveguide dimensions, angles, and positions with specific parameter values, the system achieves high alignment accuracy with relaxed manufacturing tolerances, reducing production cost.
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 approach allows for low-loss, high-accuracy vertical coupling between PICs and optical fibers, reducing fabrication costs and complexity while maintaining high bandwidth transmission capabilities.
Implementation Method 1
a reflective surface configured to change a pathway of the optical signals to direct the optical signals from the optoelectronic transducer into the low-index waveguide or from the low-index waveguide into the optoelectronic transducer
Implementation Method 2
coupled waveguide assembly comprising a low-index waveguide, a high-index waveguide proximate the low-index waveguide
Data Source
AI summary
An optical coupler and method of assembly are described that provide efficient coupling from the photonic integrated circuit (PIC) waveguide layer to external components, such as optical fibers, VCSELs, photodetectors, and gain blocks, among others. The optical coupler includes a PIC that can be supported by a printed circuit board, an optoelectronic transducer supported by the PIC that can convert between optical signals and corresponding electrical signals, and a coupled waveguide assembly. The coupled waveguide assembly includes a low-index waveguide, a high-index waveguide, and a reflective surface that changes a pathway of the optical signals to direct the optical signals from the optoelectronic transducer into the low-index waveguide or from the low-index waveguide into the optoelectronic transducer.