Backside Optical Fiber Coupling for PIC Packaging Separation
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Solution Overview
Problem
Existing optical data communication systems face challenges in achieving reliable and efficient optical signal conveyance between optical fibers and photonic integrated circuits due to incompatibilities between high-temperature flip-chip connection processes and optical fiber attachment, leading to space competition and compromised packaging configurations.
Innovation Solution
The implementation of a photonic system with an optical coupling interface on the backside of the PIC die/chip, utilizing optical reflector structures and support materials to direct light beams from optical waveguides to optical fibers, avoiding the need for keep-out-zones and cut-outs in the PIC die/chip and substrate, and enabling efficient optical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If optical fibers are attached to the same side as electrical connections, then space utilization is improved, but optical coupling reliability deteriorates due to high-temperature flip-chip processes damaging optical fibers
Solution Approach 1:
The patent divides the packaging surface into two separate sides: one side for electrical connections (flip-chip bump connections) and the opposite side for optical fiber attachments. This spatial segmentation allows each type of connection to be optimized independently, preventing the high-temperature electrical connection processes from damaging the optical fibers while still achieving high space utilization through backside mounting.
2Ease of manufacture
If keep-out-zones and cut-outs are implemented in PIC die/chip, then optical fiber attachment is enabled, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of modifying the PIC die/chip structure by creating keep-out-zones or cut-outs to accommodate optical fibers, the patent inverts the approach by mounting the optical fibers on the backside of the PIC die/chip. This eliminates the need for structural modifications to the PIC die/chip itself, thereby reducing device complexity and manufacturing difficulty while still enabling optical fiber attachment.
3Area of stationary object
If optical fibers are mounted on the front side with electrical connections, then space is saved, but optical signal transmission quality deteriorates due to interference and alignment issues
Solution Approach 1:
The patent segments the packaging configuration into separate zones for electrical and optical functions on opposite sides of the PIC die/chip. This physical separation eliminates interference between electrical signals and optical paths, ensuring high optical signal transmission quality while maintaining efficient space utilization through the backside mounting configuration.
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 enhances optical coupling efficiency by separating optical fibers from electrical connections, optimizing packaging space, and maintaining reliable optical signal transmission without compromising the PIC die/chip or packaging configuration.
Implementation Method 1
an optical reflector structure is disposed within the PIC die/chip. The optical reflector structure is configured to receive a light beam from an optical waveguide within the PIC die/chip and turn the light beam toward the second surface of the support material and toward the optical coupling interface for the optical fiber disposed on the first surface of the support material
Data Source
AI summary
A photonic system includes an optical coupling interface for an optical fiber disposed on a first surface of a support material and a PIC die/chip disposed on a second surface of the support material that is opposite from the first surface of the support material. The PIC die/chip includes an oxide stack, where a portion of the oxide stack is configured as an optical reflector structure that includes a reflecting surface configured to direct a light beam conveyed from an optical waveguide within the PIC die/chip from a first direction of travel to a second direction of travel directed toward the second surface of the support material and toward the optical coupling interface for the optical fiber disposed on the first surface of the support material. The light beam travels through the optical reflector structure and through the support material to reach the optical coupling interface for the optical fiber.