Co-Packaged PIC Optical Interface for High-Density Evanescent Coupling

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Solution Overview

Problem

Existing optical input/output (I/O) designs for photonic integrated circuits (PICs) face challenges in matching optical bandwidth density with electrical bandwidth density, particularly in multichannel wavelength division multiplexing systems, with current fiber coupling solutions like 1D V-groove arrays and 2D grating coupler arrays facing limitations in scalability and efficiency.

Innovation Solution

A high-density interposer optical interface using a thick cladding layer with turning elements and a 2D array of optical elements, such as metalenses or microlenses, to enable evanescent wave coupling and achieve optical bandwidth densities that match electrical bandwidth densities, overcoming limitations of existing 1D and 2D approaches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional fiber coupling solutions (1D V-groove arrays or 2D grating coupler arrays) are used, then optical signal transmission is achieved, but optical bandwidth density cannot match electrical bandwidth density and scalability is limited

Engineering Contradiction:

Improveoptical bandwidth densityVSAvoidscalability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from traditional 1D V-groove arrays or 2D grating coupler arrays to a three-dimensional waveguide structure embedded within a thick cladding layer. This dimensional change enables evanescent wave coupling that achieves optical bandwidth densities ≥10 Tb/s/mm, matching electrical bandwidth densities while providing scalability through the third dimension.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent embeds multiple waveguides within a thick cladding layer, creating a nested structure where waveguides are contained within the cladding material. This nesting approach enables compact integration of multiple optical channels while maintaining evanescent wave coupling efficiency, thereby achieving high bandwidth density and scalability.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If evanescent wave coupling is used to achieve high bandwidth density, then optical bandwidth density matches electrical bandwidth density, but evanescent wave decay increases

Engineering Contradiction:

Improveoptical bandwidth densityVSAvoidevanescent wave decay

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent optimizes parameters including the thickness of the cladding layer, the refractive index contrast between the waveguide core and cladding, and the spacing between waveguides. These parameter changes enable evanescent wave coupling to achieve high bandwidth density while minimizing wave decay through careful control of coupling strength and propagation distance.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high-density optical interface is implemented, then optical bandwidth density reaches ≥10 Tb/s/mm, but alignment tolerance is reduced

Engineering Contradiction:

Improveoptical bandwidth densityVSAvoidalignment tolerance

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary coupling mechanism using evanescent waves that mediate between the waveguides and the optical elements. This intermediary approach provides a more tolerant coupling mechanism compared to direct geometric alignment, as evanescent coupling depends on exponential decay rather than precise spatial matching, thereby maintaining alignment tolerance while achieving high bandwidth density.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 optical bandwidth densities greater than or equal to 10 Tb/s/mm, matching electrical bandwidth densities, while reducing evanescent wave decay and improving alignment tolerance, thus enhancing the scalability and efficiency of PICs.

Implementation Method 1

using a thick cladding layer with turning elements and a 2D array of optical elements, such as metalenses or microlenses, to enable evanescent wave coupling

Methodology Applied

Scientific EffectEvanescent wave coupling:

Implementation Method 2

when an optical signal traveling in a waveguide is incident on the boundary between the inner core and the outer cladding at an angle exceeding the critical angle, the optical signal can exhibit total internal reflection

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12523828B1High bandwidth density optical interfaces for co-packaged devices including photonic integrated circuits

Publication Date: 2026.01.13 APPLIED MATERIALS INC

AI summary

An optical interface includes a cladding layer having a plurality of inner cores and a plurality of turning elements formed therein. Each inner core the plurality of inner cores is associated with a respective turning element of the plurality of turning elements. The optical interface further includes an array of optical elements formed on the cladding layer. Each optical element of the array of optical elements is associated with a respective turning element of the plurality of turning elements.