Kilowatt-level cladding light stripper for high-power fiber laser

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• High-power fiber lasers generate significant cladding light, which can damage components.
• Existing cladding light stripping methods face challenges in efficiency and thermal management.

Purpose of the Study:

• To design and fabricate a high-power cladding light stripper (CLS) with improved efficiency and thermal performance.
• To investigate the impact of fiber etching and cascaded polymer recoating on light stripping.
• To ensure stable CLS operation under high cladding light power.

Main Methods:

• Fabrication of a hybrid CLS combining a fiber-etched CLS and a cascaded polymer-recoated CLS.
• Optimization of the numerical aperture (NA) distribution of cladding light using the etched fiber.
• Careful design of the refractive index distribution in the cascaded polymer-recoated fiber for even light leakage.
• Inclusion of multiple stages near a refractive index of 1.451 for enhanced heat dissipation.

Main Results:

• The hybrid CLS achieved an attenuation of 26.59 dB for 1187 W of cladding light.
• The highest local temperature remained below 35°C, indicating effective heat management.
• The etched fiber successfully reorganized NA distribution, increasing leakage power and flattening leakage proportion.
• The cascaded polymer-recoated fiber ensured uniform cladding light leakage.

Conclusions:

• The designed hybrid CLS effectively strips high-power cladding light with superior thermal management.
• This novel approach offers a robust solution for protecting optical components in high-power fiber laser systems.
• The combination of fiber etching and cascaded polymer recoating presents a promising strategy for advanced CLS development.