Passive Optical Coupler Alignment via V-Groove and Spherical Contact
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Solution Overview
Problem
The complexity and cost of active alignment in fiber coupling for optical devices increase with decreasing fiber core diameter, making efficient coupling challenging, especially as data rates exceed 25 Gb/s, and active alignment is labor-intensive and costly.
Innovation Solution
A passive optical coupler design featuring a first lens array and a second lens array with elongated grooves and contact elements, allowing for mechanical coupling that aligns optical axes through a point of intersection, enabling efficient fiber alignment without active monitoring, suitable for volume production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active alignment scheme is used to achieve high efficiency fiber coupling, then coupling efficiency is improved, but manufacturing cost and labor intensity increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-aligning the optical fiber with the optoelectronic chip using a mechanical alignment structure (V-grooves and spherical contact elements) before the actual coupling process. This preliminary mechanical alignment ensures that the fiber core is positioned at the correct location relative to the chip aperture, eliminating the need for costly active alignment procedures during production. The alignment is achieved through geometric constraints rather than iterative optimization.
Solution Approach 2:
The alignment structure is self-aligning through the geometric relationship between the V-grooves and spherical contact elements. When the fiber is placed in the V-groove, the spherical elements automatically position it at the correct height and lateral position. This self-service mechanism eliminates the need for external active alignment equipment and manual adjustment, enabling automated production while maintaining high coupling efficiency.
2Speed
If fiber core diameter is decreased to support higher data rates, then data transmission capability is improved, but coupling efficiency and alignment tolerance deteriorate
Solution Approach 1:
The patent applies local quality by creating a specialized alignment structure (V-grooves with specific geometry and spherical contact elements) that provides precise local positioning of the fiber core. This localized mechanical constraint ensures that even with small fiber core diameters (9 microns for single-mode), the fiber is accurately positioned relative to the chip aperture, maintaining coupling efficiency despite the reduced tolerance.
3Manufacturing precision
If active alignment is performed to optimize coupling, then coupling efficiency is improved, but production throughput and automation are reduced
Solution Approach 1:
The self-aligning mechanical structure performs the alignment function automatically without requiring active monitoring equipment or manual intervention. The V-grooves and spherical elements work together to automatically position the fiber correctly, enabling the process to be integrated into automated production lines and significantly increasing throughput compared to active alignment methods.
Solution Approach 2:
The patent extracts the alignment function from the active monitoring and adjustment process, replacing it with a passive mechanical structure. By taking out the need for active alignment equipment and procedures, the system achieves both high coupling efficiency and high production throughput through automated passive alignment.
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 design reduces packaging costs and increases machine throughput by allowing fully automated alignment, maintaining high coupling efficiency and stability across varying angular ranges and misalignment errors, suitable for high-speed data applications.
Implementation Method 1
The at least one first lens of the first lens array may be configured to receive an input light beam over an angular range
Implementation Method 2
the first lens of the first lens array may be configured to collimate a light beam generated by a laser and wherein a second lens of the first lens array may be configured to focus a light beam received from an optical fiber
Implementation Method 3
when the first and second portions may be mechanically coupled to each other the three elongated grooves may be aligned with the three contact elements, an optical axis related to the first lens array passes through a point of intersection between longitudinal axes of the three elongated grooves
Data Source
AI summary
A method for passively coupling an optical fiber to an optoelectronic chip, the method may include connecting the optical fiber to an optical cable interface of a first portion of an optical coupler; wherein the optical coupler further comprises a second portion; wherein the first portion comprises first optics that comprises a first lens array, an optical cable interface and three contact elements, each contact element has a spherical surface; and wherein the second portion comprises second optics that comprise a second lens array, and three elongated grooves; connecting the optical coupler to a substrate that supports the optoelectronic chip; and mechanically coupling the first portion to the second portion by aligning the three contact elements of the first portion with the three elongated grooves of the second portion thereby an optical axis related to a first lens array of the first portion passes through a point of intersection between longitudinal axes of the three elongated grooves, and an optical axis related to the second lens array passes through the point of intersection.