Directly Coupled Optical Interposer for PIC Alignment
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Solution Overview
Problem
Manufacturing IC packages that include photonic integrated circuits (PICs) faces challenges such as aligning optical input/output ports with optical interconnects, time-consuming testing-and-position-adjusting processes, and the risk of discarding entire packages due to undetected PIC defects before assembly.
Innovation Solution
An optical interposer assembly comprising a substrate, a PIC, and a pluggable optical connector that connects to an array of waveguides within the substrate, allowing for precise alignment and testing of PICs before integration into larger IC packages, eliminating the need for individual fiber alignment and special assembly techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fiber alignment and assembly techniques are used for PIC integration, then manufacturing complexity increases and time consumption increases, but alignment precision can be achieved
Solution Approach 1:
The patent introduces an optical interposer as an intermediary component between the PIC and the optical fiber array. The interposer includes a substrate with optical waveguides that are pre-aligned and coupled to the PIC optical ports. This intermediary structure eliminates the need for complex direct fiber-to-PIC alignment, as the waveguides provide a stable, pre-positioned optical path. The interposer acts as a mediator that simplifies the overall assembly process while maintaining high alignment precision through its integrated waveguide structure.
Solution Approach 2:
The optical waveguides are fabricated and aligned within the interposer substrate before the final PIC assembly. The waveguides are pre-positioned and coupled to the PIC optical ports in a preliminary fabrication step, allowing subsequent assembly steps to be simpler. This preliminary action of creating the waveguide structure in advance eliminates the need for time-consuming alignment adjustments during final assembly, reducing both complexity and time consumption.
2Reliability
If testing is performed before assembly, then defect detection improves, but time consumption increases due to testing-and-position-adjusting processes
Solution Approach 1:
The optical interposer enables self-testing capability where the PIC can be tested for defects before final assembly into the complete package. The interposer structure allows individual PICs to be evaluated for optical performance and defect detection in isolation. This self-service testing approach eliminates the need for time-consuming testing-and-position-adjusting cycles, as defects can be identified and filtered out before integration, improving reliability without proportionally increasing time consumption.
3Manufacturing precision
If individual fiber alignment is performed, then optical connection precision improves, but manufacturing time increases
Solution Approach 1:
The patent merges multiple individual fiber alignment operations into a single integrated waveguide structure. Instead of aligning each optical fiber individually to the PIC ports, the optical interposer combines multiple waveguides into a unified substrate where alignment is achieved once at the waveguide level. This merging of multiple alignment tasks into a single integrated structure maintains optical connection precision while dramatically reducing manufacturing time and increasing productivity.
Data Source
AI summary
A device comprises a substrate and an IC die, which may be a photonic IC. The substrate comprises a first surface, a second surface opposite the first surface, an optical waveguide integral with the substrate, and a hole extending from the first surface to the second surface. The hole comprises a first sidewall. The optical waveguide is between the first surface and the second surface, parallel to the first surface, and comprises a first end which extends to the first sidewall. The IC die is within the hole and comprises a second sidewall and an optical port at the second sidewall. The second sidewall is proximate to the first sidewall and the first end of the optical waveguide is proximate to and aligned with the optical port. The substrate may include a recess to receive another device comprising a socket.