Hybrid Optical Device Waveguide Pitch Variation Alignment
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Solution Overview
Problem
Existing hybrid integrated optical devices face challenges in achieving precise alignment of optical waveguides during flip-chip bonding, particularly in the in-plane direction perpendicular to waveguide propagation, leading to alignment errors that affect the efficiency and cost-effectiveness of high-volume data communications applications.
Innovation Solution
The optical device incorporates an optical bench with multiple optical waveguides of varying distances to compensate for alignment errors, allowing for increased tolerance in in-plane alignment by designing the waveguide pitches to ensure alignment even under reasonable misalignment conditions, using a flip-chip bonding method with spacer structures and etched trenches to facilitate precise out-of-plane alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flip-chip bonding is used to bond optical chips onto optical bench, then automated low cost assembling is enabled, but alignment precision in in-plane direction perpendicular to waveguide propagation deteriorates due to process variations
Solution Approach 1:
The patent changes the geometric parameters of the waveguide array by introducing multiple waveguides with different pitch distances. This parameter variation allows the system to tolerate alignment errors by ensuring that at least one waveguide pair maintains sufficient coupling efficiency despite misalignment, thereby resolving the contradiction between automated manufacturing and alignment precision.
Solution Approach 2:
The patent segments the single waveguide coupling path into multiple parallel coupling paths with different pitch characteristics. By dividing the optical coupling function across multiple waveguide pairs with varying distances, the system achieves redundancy that compensates for alignment errors while maintaining automated assembly capabilities.
2Manufacturing precision
If taper structure is added to expand optical beam, then alignment tolerance increases, but device complexity increases and commercial chip compatibility is lost
Solution Approach 1:
The patent makes the optical bench universal by designing it to accommodate multiple waveguide configurations with different pitches. This multi-functional design allows the same optical bench structure to work with various chip types and alignment conditions, achieving alignment tolerance without requiring complex taper structures on each chip.
3Manufacturing precision
If lens structure is added separately to expand optical beam, then alignment tolerance increases, but device complexity increases and additional alignment error is introduced
Solution Approach 1:
The patent merges the alignment tolerance function directly into the waveguide array design on the optical bench, combining multiple functions (optical transmission and alignment compensation) into a single integrated structure. This eliminates the need for separate lens components and their associated alignment procedures, reducing overall device complexity.
Data Source
AI summary
An optical device including an optical bench and an optical chip, the optical bench having multiple optical waveguides formed on its first side and the optical chip has multiple optical waveguides formed on its first side. The optical chip is flip-chip bonded onto the optical bench with its first side facing the first side of the optical bench. The distance between adjacent waveguides on the optical bench are designed to be slightly different from the distance between adjacent waveguides on the optical chip, where the latter usually is a pre-designed value under certain conventions. The difference amount is properly designed such that under reasonable misalignment between the optical chip and the optical bench in the in-plane direction perpendicular to waveguide propagation one can always find that one of the multiple waveguides is aligned sufficiently well with the corresponding waveguide on the optical chip.