Multi-Depth Optical Connect Grooves for PIC Die Alignment
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Solution Overview
Problem
Current photonic integrated circuit (PIC) dies face challenges in optical coupling with external fibers due to precise alignment requirements and limited active device space, leading to reduced data transmission rates and density, as well as cross-talk issues from adjacent fibers.
Innovation Solution
The PIC die features multiple depth optical connect grooves, allowing optical fibers to be aligned with optical components at different vertical and lateral depths within the die, optimizing the use of active layers and reducing cross-talk by positioning fibers away from active devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral optical connect grooves are formed adjacent the active layer to connect external optical fibers to the PIC die, then optical coupling is achieved, but the grooves occupy significant fraction of the PIC footprint that could otherwise be used for active devices
Solution Approach 1:
The patent transitions from lateral optical connections to vertical optical connections by forming optical connect grooves that extend through multiple layers of the PIC die in the vertical direction. This dimensional change allows optical fibers to connect to optical waveguides from the top surface rather than from the lateral edge, thereby freeing up lateral footprint space for additional active devices while maintaining optical coupling functionality.
2Productivity
If multiple optical fibers are positioned in close lateral proximity to increase data transmission density, then data transmission capacity is improved, but cross-talk between optical signals increases
Solution Approach 1:
The patent arranges optical fibers and their corresponding optical waveguides in the vertical dimension rather than lateral arrangement. By stacking optical connect grooves and waveguides at different vertical levels, multiple optical channels can be densely packed without lateral proximity, thereby increasing data transmission density while eliminating cross-talk that arises from lateral fiber placement.
Solution Approach 2:
The patent segments the optical connection structure into multiple vertically separated layers, with each layer containing optical connect grooves and waveguides at specific vertical positions. This segmentation isolates optical signals in the vertical dimension, preventing cross-talk between channels while maintaining high transmission density through multi-layer integration.
3Reliability
If precise alignment tolerances are observed when attaching input and output fibers to on-chip optical waveguides, then efficient light coupling is achieved, but the complexity of the packaging integration scheme increases
Solution Approach 1:
The patent incorporates alignment features directly into the optical connect grooves during the PIC die fabrication process, before final assembly. The grooves are pre-formed with precise geometries that guide and self-align optical fibers during packaging, thereby achieving efficient light coupling while reducing the complexity of the overall packaging integration scheme.
Data Source
AI summary
A photonic integrated circuit (PIC) die are provided. The PIC die includes a set of optical connect grooves including a first groove aligning a core of a first optical fiber positioned with a first optical component in a first layer at a first vertical depth in a plurality of layers of a body of the die, and a second groove aligning a core of a second optical fiber positioned therein with a second optical component in a second, different layer at a second different vertical depth in the plurality of layers. The grooves may also have end faces at different lateral depths from an edge of the body of the PIC die. Any number of the first and second grooves can be used to communicate an optical signal to any number of layers at different vertical and/or lateral depths within the body of the PIC die.