Double Bottleneck Fiber Amplifier for High Power Tm Laser
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Solution Overview
Problem
High power Thulium (Tm) fiber lasers face challenges in operating efficiently at high power levels and maintaining a compact structure, as increasing the number of erbium-doped fiber lasers leads to a more complex and less compact system.
Innovation Solution
A high power fiber laser system utilizing a multimode Erbium-doped or Ytterbium/Er-doped double bottleneck-shaped fiber amplifier to radiate multimode pump light into a single mode Tm fiber laser, featuring a compact design with a double clad Tm fiber for effective pump light absorption and reduced nonlinear effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of SM Er fiber lasers is increased to achieve higher power output, then the power level is improved, but the system complexity and size increase
Solution Approach 1:
The patent combines multiple Er-doped fiber lasers into a single integrated amplifier unit with a shared resonant cavity and gain medium. This merging approach allows the system to achieve high power output through the amplifier's gain multiplication capability rather than by simply increasing the number of separate laser modules, thereby maintaining system compactness while delivering the required power levels.
Solution Approach 2:
The invention transitions from a horizontal scaling approach (adding more laser modules in parallel) to a vertical scaling approach (using a single amplifier with high gain). The double-clad fiber amplifier enables power scaling through the amplification dimension rather than through numerical multiplication of laser sources, effectively resolving the complexity-power tradeoff.
2Power
If the number of SM Er fiber lasers is increased to achieve higher power output, then the power level is improved, but the system size increases
Solution Approach 1:
The patent consolidates multiple laser functions into a single amplifier-based system with a shared resonant cavity. This integration eliminates the need for multiple separate laser modules, reducing the overall system volume while maintaining the capability to deliver high power output through the amplifier's gain mechanism.
Solution Approach 2:
The design employs a nested structure where the resonant cavity is integrated within the amplifier assembly, and the double-clad fiber structure allows the pump light to be efficiently coupled into the gain medium. This nested arrangement maximizes space utilization and minimizes the overall system footprint while achieving high power output.
3Power
If Tm laser operates at high power levels, then the power output is improved, but the performance degradation occurs
Solution Approach 1:
The patent introduces an Er-doped fiber amplifier as an intermediary stage between the pump source and the Tm-doped laser medium. This amplifier pre-conditioning the pump light and providing controlled gain before the signal reaches the Tm laser, thereby stabilizing the overall system performance at high power levels and preventing direct degradation of the Tm laser's reliability.
Solution Approach 2:
The system employs prior cushioning by using the Er amplifier to buffer and stabilize the pump energy delivery to the Tm laser. This preliminary energy conditioning prevents sudden power fluctuations and thermal shocks that could degrade the Tm laser's performance, ensuring stable operation at high power levels.
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 system achieves higher efficiency and stability at high power levels with minimal degradation in output power, maintaining a compact structure and efficient operation, suitable for industrial, medical, and airborne applications.
Implementation Method 1
a multimode (MM) Erbium-doped ("Er") or ytterbium (Yb)/Er-doped double bottleneck-shaped fiber amplifier which radiates a multimode pump light
Implementation Method 2
fiber amplifier which radiates a multimode pump light coupled into a SM Tm fiber laser
Implementation Method 3
double clad Tm fiber for effective pump light absorption
Data Source
AI summary
A high power fiber laser system is configured with a pump cascade and a laser cascade. The pump cascade includes a fiber amplifier provided with a MM core which is doped with ions of rare-earth element including either Er or Yb/Er. The MM core of fiber amplifier is configured with a double bottleneck-shaped cross section. The laser cascade has a fiber laser configured with a core which is doped with Tm ions. The pump light generated by the amplifier is coupled into the upstream end of the Tm laser.