Optic Fiber Amplifier Deformable Structure Brillouin Threshold
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Solution Overview
Problem
Existing optical fiber amplifiers face limitations in achieving a high Brillouin threshold due to constraints such as complex machinery, difficulty in modifying elongation profiles, and thermal management issues, which affect the spectral shape of the Brillouin gain and overall performance.
Innovation Solution
An optical fiber amplifier with a deformable structure that allows the amplifying optical fiber to be wound in coils, enabling adjustable elongation profiles to optimize the Brillouin gain, combined with a method of fixing the fiber at specific points to minimize delamination risks and optimize elongation values, thereby increasing the Brillouin threshold without compromising the spatial quality of the beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amplifying optical fiber is stretched to increase the Brillouin threshold, then the Brillouin threshold increases, but the fiber may delaminate or break
Solution Approach 1:
The fiber is divided into multiple sections, each wrapped around different portions of the deformable structure. This segmentation allows the total elongation to be distributed across multiple segments, preventing any single point from experiencing excessive stress that would cause delamination or breakage.
Solution Approach 2:
Different sections of the fiber are subjected to different elongation levels by wrapping them around different portions of the deformable structure. This local differentiation allows optimization of the Brillouin threshold while maintaining fiber integrity in critical regions.
2Reliability
If complex machinery is used to achieve high Brillouin threshold, then the Brillouin threshold increases, but the device complexity increases
Solution Approach 1:
The patent employs a deformable structure that can be dynamically adjusted to modify the elongation profile of the fiber. This dynamic capability allows tuning of the Brillouin threshold without requiring complex fixed machinery, as the same structure can be reconfigured as needed.
Solution Approach 2:
The Brillouin threshold is controlled by changing the elongation parameter of the fiber through the deformable structure. By adjusting the deformation of the structure, the elongation profile is modified, thereby tuning the Brillouin threshold without complex equipment.
3Manufacturing precision
If the elongation profile is modified to optimize Brillouin gain, then the spectral shape of Brillouin gain improves, but the manufacturing difficulty increases
Solution Approach 1:
The deformable structure enables dynamic modification of the elongation profile after manufacturing. This means the spectral shape can be optimized by adjusting the deformation state rather than requiring precise manufacturing of fixed elongation features, significantly easing the manufacturing process.
Solution Approach 2:
The fiber is wrapped around the deformable structure in a preliminary configuration during manufacturing, but the final elongation profile is established by deforming the structure later. This preliminary action simplifies manufacturing while allowing subsequent optimization of the spectral shape.
4Stability of the object's composition
If the fiber is fixed at multiple points to prevent delamination, then the fiber stability improves, but the elongation optimization becomes more difficult
Solution Approach 1:
The deformable structure allows the elongation profile to be adjusted dynamically while maintaining fiber stability through multiple fixation points. The structure can be deformed to different states, enabling elongation optimization without compromising the stability provided by the fixation points.
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 effectively raises the Brillouin threshold while allowing for easy tailoring of the spectral shape of the Brillouin gain during amplifier fine-tuning phases, enhancing the performance and reliability of the optical fiber amplifier by reducing the risk of delamination and maintaining spatial quality.
Implementation Method 1
a structure comprising a deformable part around which at least one part of said amplifying optical fiber is wound in the form of coils, said coils being in contact with a surface of said deformable part, the rubbing of said optical fiber on said surface causing during the deformation of said deformable part an elongation of said amplifying optical fiber
Implementation Method 2
a portion of the optical fiber is doped with a substance able to engender an optical gain, for example dopant ions of rare earth ion type, and is pumped optically with a laser pump beam so as to place the dopant ions in an excited state. When a signal beam passes through the doped fiber portion, it de-excites the ions by laser effect, producing a photon identical to the incident photon.
Implementation Method 3
saturation of the laser power transmitted due to a nonlinear effect in the fiber called stimulated Brillouin scattering (or the SBS effect) is observed beyond a power threshold (Pth). Beyond this power threshold, called the Brillouin threshold, the extra laser power is reflected in the form of a wave termed a Stokes wave resulting from the interaction of the incident wave with auto-generated acoustic waves
Implementation Method 4
The Stokes wave exhibits an optical frequency νs shifted in frequency (by the Doppler effect) according to νs=ν−νB where ν is the frequency of the incident wave and νB, called the Brillouin frequency, is the frequency of the acoustic wave
Data Source
AI summary
According to one aspect, the invention relates to an optic fiber amplifier having a high Brillouin threshold, and including: an amplification optic fiber (16) comprising a core and a sheath and suitable for amplifying a signal beam travelling in said core; means for coupling the signal beam in an input end of said amplification optic fiber; means for coupling a pump laser beam for pumping said amplification optic fiber; a structure (330, 340) including a deformable portion around which at least one portion of said amplification optic fiber is wound in the shape of turns, said turns being in contact with a surface of said deformable portion, wherein the friction of said optic fiber on said surface resulting, during the deformation of said deformable portion, in an elongation of said amplification optic fiber according to an elongation profile that varies from one turn to the other.