Co-Packaged Optical I/O Interface for Short PCB Signal Paths
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Solution Overview
Problem
High-speed electronic subsystems with large I/O counts face bottlenecks in communication due to long electrical links, power consumption, and signal integrity issues, particularly when connecting to pluggable optical transceivers, which increase complexity and cost.
Innovation Solution
Implementing photonic integrated circuits (PICs) on the opposite side of the PCB from electronic circuits, using co-packaging with a Communication Interface Unit (CIU) that includes electrical vias for direct connections, reducing the need for long electrical traces and enabling improved signal integrity, thermal management, and power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If long electrical links are used to connect electronic I/O pins, then the number of connections can be maintained, but power consumption increases and signal integrity deteriorates
Solution Approach 1:
The patent replaces long electrical connections with optical connections using photonic integrated circuits. Electrical signals are converted to optical signals for transmission, eliminating the need for long electrical traces on the PCB. This substitution reduces power consumption and improves signal integrity while maintaining the required number of connections.
Solution Approach 2:
The patent transitions from a two-dimensional PCB routing approach to a three-dimensional co-packaged architecture where electronic and photonic circuits are vertically integrated. The photonic circuit die is positioned adjacent to the electronic circuit die, with electrical connections made through vertical vias rather than horizontal PCB traces, reducing connection length and improving performance.
2Productivity
If the number of high-speed I/O pins increases, then communication bandwidth is improved, but routing complexity and difficulty increase
Solution Approach 1:
The patent merges electronic and photonic circuits into a single co-packaged unit. The photonic circuit die is directly coupled to the electronic circuit die, integrating multiple functions (electronic processing and optical transmission) into one compact assembly. This reduces the overall system complexity compared to separate electrical routing for each connection.
Solution Approach 2:
The patent uses vertical stacking and adjacent positioning of circuit dies to reduce routing complexity. Instead of routing numerous high-speed signals across a large PCB area, connections are made through short vertical vias or adjacent die interfaces, dramatically simplifying the routing architecture while supporting high bandwidth.
3Quantity of substance
If electrical connections are made through PCB traces, then connectivity is achieved, but signal integrity issues arise due to trace length
Solution Approach 1:
The patent substitutes electrical signal transmission with optical signal transmission for the connection paths. Optical signals are immune to electromagnetic interference and signal degradation that plagues long electrical traces, thereby maintaining signal integrity while preserving the required number of connections.
Solution Approach 2:
The patent reduces the physical length of connection paths by transitioning from horizontal PCB routing to vertical or adjacent-die connections. This dimensional change minimizes the distance signals must travel, reducing exposure to sources of interference and degradation, thereby improving signal integrity.
4Ease of manufacture
If traditional electrical routing methods are used, then manufacturing is straightforward, but cost increases due to complexity impairments
Solution Approach 1:
The patent combines electronic and photonic manufacturing processes into an integrated co-packaging workflow. By designing the system as a unified structure with predetermined connection points and standardized interfaces, the overall manufacturing complexity is reduced despite the advanced technology involved, as components can be manufactured separately and assembled with precision.
Data Source
AI summary
An optical input/output (I/O) system includes at least one electronic circuit die on at least one first substrate on a first side of a printed circuit board (PCB), where the at least one electronic circuit die includes at least 4 electrical inputs and at least 4 electrical outputs that are each configured to operate with a speed of at least 10 Gb/s. The optical I/O system also includes at least one photonic circuit die on at least one second substrate on a second side of the PCB, opposite the first side of the PCB. A plurality of electrical connections are implemented through the PCB, and electrically connect the at least one photonic circuit die with the at least 4 electrical inputs and the at least 4 electrical outputs of the at least one electronic circuit die.