A 100-W Cladding Power Stripper with Ultra-Low Backscattering for $20/400-\mu \mathrm{m}$ Large Mode Area Double Clad Fiber

We experimentally demonstrate a 100-W cladding light stripper (CLS) with ultra-low backscattering. We fabricated a CLS based on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20/400-\mu m$</tex> LMA-DCF by HF-free chemical etching. The stripping efficiency and backscattering level were <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 98.9 \%$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 0.13 \%$</tex>, respectively.