Planar Double-Spiral Fiber Package for TMI Suppression
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Solution Overview
Problem
Existing fiber laser and amplifier designs face challenges with fiber management, visibility, and thermal modal instability due to non-planar coil configurations, leading to potential damage and inefficiencies.
Innovation Solution
A double spiral active fiber package with coplanar grooves allows for complete visibility and easy integration of fibers, suppresses thermal modal instability, and prevents twists and bends, using a potting compound and thermal management system to secure and cool the fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fiber is coiled in a non-planar configuration to accommodate long lengths, then the fiber can be managed, but the fiber is not visible along the entire length and splicing becomes difficult
Solution Approach 1:
The patent transitions from a three-dimensional non-planar coil to a two-dimensional planar configuration. The fiber is arranged in a planar coil where the entire length lies substantially in one plane, enabling visibility along the entire fiber length while maintaining effective accommodation of long fiber lengths through the coiled geometry.
2Ease of operation
If the fiber is coiled to accommodate long lengths, then the fiber can be managed, but twists and bends may occur leading to additional losses
Solution Approach 1:
The patent employs a planar coil configuration with controlled curvature radii. The fiber is coiled with a first curvature radius in the radial direction and a second curvature radius in the axial direction, both carefully controlled to prevent excessive bending losses while accommodating long fiber lengths. The smooth curved geometry eliminates sharp bends and twists.
3Ease of operation
If a multi-layer structure is used to manage the fiber, then the fiber can be accommodated, but fiber visibility is lost and loading becomes difficult
Solution Approach 1:
The patent simplifies the structure from multi-layer to single-plane configuration. The fiber lies substantially in one plane, eliminating the complexity of multi-layer stacking. This planar arrangement allows direct visual access to the entire fiber length, enabling easy monitoring during loading and simplifying the overall manufacturing process.
4Shape
If the fiber enters and exits at different heights, then the coil can be formed, but splicing becomes not straightforward
Solution Approach 1:
The patent positions both the input and output fiber ends at substantially the same height within the planar coil configuration. This equipotential arrangement at the same elevation level facilitates straightforward splicing operations, as both ends are accessible at the same plane without requiring complex positioning or height adjustment mechanisms.
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 enhances fiber visibility and thermal stability, increasing laser power by at least 50% while preventing damage and maintaining efficient operation.
Implementation Method 1
a substantially planar cooling plate situated underneath the plate-shape base... allowing for cooling of the active fiber and or splices
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present invention provides an active fiber package for use in a fiber laser, amplifier, or ASE source comprising: a plate-shape base comprising a groove having a configuration of at least two spirals for receiving and fixedly holding an active fiber therein, said at least two spirals are coplanar enabling visibility of said active fiber, the outer loop of one spiral transitioning smoothly to the outer loop of another spiral, and the inner loop of each one of said spirals transitioning smoothly into a relatively short straight section; wherein a portion of said straight section of one of said spirals spliced to a coupling fiber, and wherein multiple inner loops of each one of said spirals in proximity to said straight section having a relatively low radius of curvature for enabling tight coiling of said active fiber, thus, for reducing thermal modal instability (TMI) and increasing lasing power.