Optical Integrated Circuit With Inserted Micro-Mirror
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Solution Overview
Problem
The existing manufacturing processes for optical integrated circuits with light path turning mirrors inside optical waveguides face challenges in fabricating mirrors within silica waveguides due to difficulties with dry etching techniques, leading to complex and costly processes with unsatisfactory mirror quality and reproducibility.
Innovation Solution
A method involving the separate manufacturing of micro-mirrors from the optical integrated circuit process, which are then inserted into grooves within the waveguides, allowing for a higher quality mirror surface and reduced manufacturing costs, using materials like silicon, glass, and plastics, and employing anisotropic dry etching for groove formation with tilted sidewalls to facilitate vertical light coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dry etching techniques are used to fabricate mirrors within silica waveguides, then light path turning function is achieved, but manufacturing complexity and cost increase while mirror quality and reproducibility deteriorate
Solution Approach 1:
The patent divides the manufacturing process into two independent parts: (1) fabricating the silica waveguide structure with groove using standard PLC processes, and (2) separately manufacturing micro-mirrors using suitable techniques then bonding them into the grooves. This segmentation allows each component to be optimized independently, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The mirror fabrication is extracted from the waveguide manufacturing process. Instead of attempting to fabricate mirrors directly within the silica waveguide using dry etching, the mirrors are manufactured separately using appropriate techniques and then bonded into pre-formed grooves in the waveguide structure. This extraction eliminates the manufacturing precision problems associated with in-situ mirror fabrication.
2Ease of manufacture
If dry etching techniques are used to fabricate mirrors within silica waveguides, then light path turning function is achieved, but device complexity and cost increase
Solution Approach 1:
By segmenting the device into a standard silica waveguide component and a separately manufactured mirror component, the patent reduces overall device complexity. The waveguide portion can be produced using mature PLC processes, while the mirror portion is a simple bonded element, avoiding the need for complex integrated mirror-fabrication equipment.
Solution Approach 2:
The groove structure in the silica waveguide serves multiple functions: it provides mechanical support for the mirror, defines the mirror's position and orientation, and enables optical coupling. This multi-functionality reduces the need for additional structural elements, simplifying the overall device design.
3Ease of manufacture
If separate manufacturing of micro-mirrors is used, then manufacturing cost and complexity are reduced, but integration difficulty increases
Solution Approach 1:
The waveguide grooves are prepared in advance with precise dimensions, surface treatments, and positioning features before mirror bonding. This preliminary action ensures that when mirrors are separately manufactured and then integrated, they fit precisely and reliably into the waveguide structure, maintaining high integration reliability despite the separate manufacturing process.
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 manufacturing process, reduces optical power loss, and lowers costs by using easily fabricated micro-mirrors with improved quality, enabling efficient light coupling and reducing back reflections through precise angle control.
Implementation Method 1
a micro-mirror which reflects incident light from the core layer vertically upward to the light receiving element
Implementation Method 2
employing anisotropic dry etching for groove formation with tilted sidewalls
Data Source
AI summary
An optical integrated circuit comprises optical waveguides, grooves formed by etching the upper cladding layer, the core layer and all or parts of the lower cladding layer close to a end section of the optical waveguide to intercept light transmitted through the core layer of the optical waveguide or to couple light into the core layer, a plurality of bonding pads formed around the groove, micro-mirrors and active optical elements. Such a PLC based optical integrated circuit and a method of manufacturing the same provides a low-cost manufacturing of optical integrated circuits and high quality mirrors for vertical optical coupling scheme.