High-Power Cladding Light Stripper with Vapor Deposition of Polyethersulfone

Fiber lasers are one of the most preferred of today's efficient coherent light sources in many application areas with their advantages such as stability, compactness, robustness, diffraction-limited beam quality, large available bandwidth, tuneability, and independence from alignment [1] . With the technological and material-based advances in fiber laser, it has become possible to reach multikilowatt output powers. In high-power fiber lasers, cladding light power can reach more than hundreds of watts, this unwanted light may affect system performance and beam quality greatly. The unwanted cladding light can be produced by amplified spontaneous emission (ASE) which cannot guide in the core, signal loss at fiber core caused by excessive bending, unabsorbed pump light in the active medium and splicing loss of the junction points. The elimination process of unwanted cladding light for the high-power fiber amplifiers became an important issue [2] . There are several techniques to extract the unwanted cladding light from the fiber laser system such as surface texturization by using mechanical system and CO 2 laser ablation, chemical etching, soft metal coating and high index polymer coating [3] , [4] .