Optoelectronic Chip Alignment Using Liquid-Filled Gap Inspection
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Solution Overview
Problem
The complexity of fiber coupling in optical devices increases with decreasing fiber core diameter, making efficient light coupling challenging, especially as data rates exceed 25 Gb/s, and active alignment methods are costly and labor-intensive, unsuitable for volume production.
Innovation Solution
A method involving temporarily filling the gap between an optical mount and an optoelectronic chip with a liquid to inspect and determine the spatial relationship, allowing for passive alignment using pre-defined marks and automated machines, reducing the need for active alignment and lowering production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active alignment scheme is used to achieve high efficiency fiber coupling, then coupling efficiency is improved, but production cost and labor intensity increase significantly
Solution Approach 1:
The patent replaces the active alignment mechanism (which requires electrical powering and real-time optical monitoring) with a passive alignment mechanism using pre-defined alignment marks. The alignment marks are physically imprinted on the chip and mount, allowing mechanical positioning to be determined through optical inspection of the marks themselves, eliminating the need for complex active monitoring systems.
Solution Approach 2:
The alignment marks are pre-defined and permanently imprinted on the optoelectronic chip and optical mount during manufacturing. This preliminary action allows the alignment information to be embedded in advance, eliminating the need for complex real-time alignment procedures during assembly. The marks are ready for immediate use in passive alignment during final assembly.
2Measurement precision
If active alignment is performed manually, then alignment precision is improved, but production time and labor cost increase
Solution Approach 1:
The alignment marks are designed to be self-aligning features that are automatically positioned during the assembly process. The marks on the chip and mount serve as built-in reference points that guide the alignment process without requiring external intervention or complex measurement systems. This self-service approach enables automated optical inspection systems to quickly and accurately determine alignment status.
3Speed
If fiber core diameter is decreased to support higher data rates, then data transmission capability is improved, but coupling efficiency deteriorates due to stricter spot size and angular control requirements
Solution Approach 1:
The patent changes the alignment approach from active optical parameter adjustment to passive mechanical position-based alignment. By using pre-defined alignment marks that encode spatial relationship information, the system transforms the coupling problem from one requiring real-time optical parameter control to one solved by precise mechanical positioning during assembly, thereby maintaining coupling efficiency with smaller fiber core diameters.
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 simplifies the fiber coupling process, reduces production costs, and enhances the accuracy and efficiency of optical device assembly by enabling passive alignment, suitable for high-volume production and maintaining high coupling efficiency even at higher data rates.
Implementation Method 1
The filling may include positioning one or more drops of the liquid at a vicinity of the lens and allowing capillary forces to move the one or more drops towards the lens
Implementation Method 2
The small core diameter imposes stringent limitations on the coupling efficiency that are directly affecting the overall cost of the device. In principle, the light from a laser source is routed via a lens to the fiber input face
Data Source
AI summary
A method for determining a spatial relationship between an optoelectronic chip and an optical mount, the method may include temporarily filling, by a liquid, a gap formed between a lens of the optical mount and the optoelectronic chip, while the optical mount contacts the optoelectronic chip; inspecting an optical component of the optoelectronic chip through the lens and through the liquid that fills the gap; and determining the spatial relationship between the optoelectronic chip and the optical mount based on the outcome of the inspecting of the optical component.