Vanishing Core Optical Coupler Array for Low-Loss Fiber Interface
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Solution Overview
Problem
Existing optical couplers face challenges in interfacing dissimilar NA waveguide devices and multichannel devices with conventional optical fibers, particularly in maintaining low-loss, high-accuracy connections due to differences in core sizes, NAs, and channel spacing, leading to increased insertion losses and decreased coupling coefficients.
Innovation Solution
A multichannel optical coupler array with a common single coupler housing structure and vanishing core waveguides, featuring a gradual refractive index transition and specific refractive index relationships, along with a transversely contiguous medium and strategically designed holes or gaps, to facilitate efficient optical coupling between optical fibers and devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional optical fibers are used to interface with multichannel devices having channel spacing less than fiber diameter, then device integration is enabled, but insertion losses increase and coupling coefficients decrease due to size and NA mismatches
Solution Approach 1:
The patent introduces an optical coupler array as an intermediary component between conventional optical fibers and multichannel waveguide devices. This coupler array serves as a mediator that receives light from conventional fibers and efficiently couples it to closely spaced waveguides, resolving the interface compatibility issue without requiring direct connection between dissimilar components.
Solution Approach 2:
The invention segments the optical coupling function into multiple independent channels within a single coupler array structure. Each channel can independently couple to individual waveguides, allowing the system to handle multiple wavelengths or spatial modes simultaneously while maintaining efficient coupling for each individual channel.
2Loss of energy
If waveguides with different NA are used to match fiber specifications, then coupling efficiency improves, but device complexity increases due to custom waveguide designs
Solution Approach 1:
The patent employs gradual index transition regions that change the refractive index parameter continuously between the fiber and waveguide. This parameter change approach allows the system to bridge NA mismatches without requiring custom-designed waveguides, using standard waveguide structures with modified coupling regions instead.
Solution Approach 2:
The invention applies different refractive index characteristics to different regions of the coupler array. The coupling regions have modified refractive indices to facilitate efficient coupling, while the waveguide regions maintain standard characteristics. This local differentiation allows efficient coupling without changing the overall waveguide design.
3Measurement precision
If precise positioning of multiple waveguides is achieved, then coupling accuracy improves, but manufacturing precision requirements increase
Solution Approach 1:
The coupler array incorporates self-aligning features such as mechanical guides, alignment marks, and refractive index gradients that automatically position waveguides relative to each other and to the input fibers. This self-service mechanism reduces the need for high-precision external positioning systems and simplifies manufacturing.
Solution Approach 2:
The invention merges multiple alignment functions into a single integrated coupler array structure. By combining mechanical alignment features with optical coupling elements, the design achieves precise positioning without requiring separate alignment systems for each waveguide, thereby reducing overall manufacturing complexity.
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 solution enables low-loss, high-accuracy optical coupling with improved alignment and reduced insertion losses, preserving waveguiding properties and enhancing coupling efficiency up to 100% between optical fibers and devices.
Implementation Method 1
gradual refractive index transition and specific refractive index relationships
Implementation Method 2
preserving waveguiding properties
Data Source
AI summary
A multichannel optical coupler array can include a coupler housing structure and longitudinal waveguides. At least one of the longitudinal waveguides can be a vanishing core waveguide having an inner vanishing core having a first refractive index (N-1), an outer core having a second refractive index (N-2), and an outer cladding having a third refractive index (N-3). A refractive index transition between N-1 and N-2 can have a function form N(r), where r is a transverse distance from the inner vanishing core center. The function N(r) can be a smooth function having a positive average of the second derivative or function N(r) can be a step function with at least one step approximating the smooth function. The coupler housing structure may have non-circular holes formed by convex-shaped housing structure elements.