Microlens Array Alignment Using Single-Mode Optical Fibers
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Solution Overview
Problem
The existing microlens arrays face challenges in achieving high positional accuracy during alignment and connection with optical circuits, leading to complex mounting operations and increased costs due to the need for precise alignment of the microlens center with the guided mode field distribution in optical waveguides.
Innovation Solution
The microlens array incorporates single-mode optical fibers for alignment, arranged parallel to gradient index multimode optical fibers, allowing for precise alignment and connection without the need for a slit, thereby simplifying the alignment process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microlens array uses conventional multimode optical fibers with large aperture, then the light collecting capability is improved, but the positional alignment accuracy with the optical waveguide deteriorates
Solution Approach 1:
The invention divides the optical fiber array into two distinct segments: alignment optical fibers with small core diameters (5-10 μm) for precise positional alignment, and signal optical fibers with large core diameters (50-100 μm) for light collecting. This segmentation allows each segment to optimize its function independently, resolving the contradiction between alignment precision and light collection efficiency.
Solution Approach 2:
The alignment optical fibers act as intermediary elements between the microlens array and the optical waveguide. By using these dedicated alignment fibers with small core diameters, the system achieves precise positional alignment without requiring the signal-carrying optical fibers to have alignment precision, thus mediating the contradiction between large aperture and positioning accuracy.
2Reliability
If the microlens array aperture is increased to improve light collection, then the light receiving capability is improved, but the complexity of alignment operation increases
Solution Approach 1:
The invention segments the optical fiber functions into alignment-specific fibers and signal-specific fibers. The alignment optical fibers with small core diameters provide sharp light intensity peaks that are easy to detect and align, simplifying the alignment operation. The signal optical fibers with large core diameters maintain high light receiving capability, thus resolving the contradiction between light collection and alignment ease.
Solution Approach 2:
The alignment optical fibers perform the self-service function of providing alignment guidance through their small core diameter characteristics. When light passes through these fibers, they naturally produce sharp intensity peaks that automatically indicate optimal alignment positions, eliminating the need for complex external alignment tools or procedures.
3Manufacturing precision
If dedicated alignment devices and slits are introduced to improve alignment precision, then the positional accuracy is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the alignment function from the signal transmission function by introducing dedicated alignment optical fibers. These alignment fibers are integrated into the optical fiber array structure itself, eliminating the need for separate external alignment devices, slits, or complex alignment tooling, thus achieving high positional accuracy without increasing overall device complexity.
Solution Approach 2:
The alignment optical fibers serve multiple functions: they provide positional alignment guidance during assembly, maintain the structural integrity of the optical fiber array, and can potentially be used for monitoring purposes. This multi-functionality reduces the need for separate dedicated alignment devices, simplifying the overall system while maintaining high positional accuracy.
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 configuration ensures high positional accuracy and facilitates easy connection of the microlens array with optical circuits, reducing manufacturing complexity and costs while maintaining high alignment precision.
Implementation Method 1
a gradient index (hereinafter referred to as GI) multimode optical fiber used in optical communication has a square refractive index distribution in which the refractive index is maximum at the core center and exhibits a good lens function
Implementation Method 2
single-mode optical fibers arranged at both sides of the array structure so that their optical axis is parallel to the optical axis of the gradient index multimode optical fibers and having a length in the optical axis direction the same as the length of the gradient index multimode optical fibers and a guided mode diameter smaller than an aperture of the gradient index multimode optical fibers
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
This invention provides a microlens array, which maintains high positional accuracy with respect to an optical circuit such as a waveguide and facilitates connection operation, and an optical transmission component including the microlens array. Solution The microlens array according to the present invention is provided with a plurality of microlenses 1 arranged in an array structure and having the same length in the optical axis direction and optical fibers 9 for alignment arranged at both ends of the array structure so that the optical axis is parallel to the optical axis of the microlens 1 and having a length in the optical axis direction the same as the length of the microlens 1 and a guided mode diameter smaller than an aperture of the microlens 1.