Micro-Mirror Edge Coupler for Demountable PIC Fiber Alignment
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Solution Overview
Problem
Existing photonic integrated circuits (PICs) face challenges in efficiently coupling optical fibers due to size mismatches between single-mode waveguides and optical fibers, leading to high insertion losses and misalignment issues, particularly with polymer connectors that deform under external loads and temperature changes.
Innovation Solution
A demountable edge coupler with a micro-mirror optical bench (MOB) that includes a mirror array and a base, allowing for separable and reconnectable coupling between optical fiber arrays and PIC devices, using malleable metals like Kovar or stainless steel for precise alignment and reshaping light paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polymer connector components are used to achieve alignment, then ease of assembly is improved, but dimensional stability deteriorates under temperature changes and external loads
Solution Approach 1:
The patent changes the material parameter from polymer to metal (Invar or Kovar), fundamentally altering the dimensional stability characteristic while maintaining alignment functionality. This material substitution resolves the contradiction by eliminating polymer deformation under temperature and load while preserving ease of assembly through the same connector mechanism.
Solution Approach 2:
The patent employs composite material construction by combining metal base materials (Invar or Kovar) with optical components to create a connector that achieves both dimensional stability and optical performance. This composite approach allows the metal substrate to provide thermal and mechanical stability while the optical elements maintain coupling efficiency.
2Device complexity
If direct coupling between single-mode waveguides and optical fibers is attempted, then device complexity is reduced, but coupling efficiency deteriorates due to size mismatch
Solution Approach 1:
The patent introduces an intermediary coupling mechanism using the metal connector component that facilitates efficient light transfer between waveguides and optical fibers. This intermediary structure acts as a mediator that bridges the size and mode mismatch, enabling effective coupling without requiring complex multi-element systems.
3Reliability
If permanent optical fiber attachment is used, then connection reliability is improved, but adaptability deteriorates as the connection cannot be demounted or reused
Solution Approach 1:
The patent transforms the static permanent attachment into a dynamic demountable connection using the metal connector that can be repeatedly assembled and disassembled. This dynamic design maintains connection reliability during use while enabling adaptability for reconfiguration, maintenance, and reuse, resolving the contradiction between permanence and versatility.
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
The edge coupler enables efficient, reliable, and cost-effective optical coupling with improved alignment tolerances, maintaining high data rates and reducing optical losses, while being reusable and adaptable to temperature variations.
Implementation Method 1
Each mirror includes a structured reflective surface profile that turns light between a first light path along a first (horizontal) direction in a plane substantially parallel to the top surface and a second light path along a second (vertical) direction outside the plane
Implementation Method 2
the coefficient of thermal expansion (CTE) of polymers is much larger than the CTE of materials that are commonly used in PIC devices. Therefore, temperature cycles cause misalignment between the optical fibers and the optical elements on the PIC devices
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
An edge coupler having an optical bench with a mirror array. Each mirror bends, reflects and/or reshapes incident light. The edge coupler is optically coupled to the optical elements in a PIC chip which direct light to the edge of the PIC chip. The edge coupler provides a demountable, passively aligned coupling between an optical fiber array and the PIC chip. The edge coupler may be a free space edge coupler without any optical element between the mirror array and the optical elements of the PIC chip, or may include grooves each receiving a section of optical fiber with its longitudinal axis along the first light path and terminating substantially at or extending beyond the edge of the edge coupler. The optical fiber array may include an optical fiber connector terminating and supporting the ends of the optical fibers in optical alignment with the mirror array of the edge coupler.