High-Strength High-Efficiency Cladding Light Strippers with CO_2 Laser Ablation

摘要

All-glass microstructured high-power cladding light strippers (CLSs) capable of handling hundreds of watts of cladding power or more are highly desired in cladding-pumped high power fiber laser systems. In this paper we demonstrate high strength, high efficiency CLSs with tensile strength more than 50 N, temporary bending diameter less than 6 cm and power stripping efficiency more than 7 dB/cm. These CLSs are fabricated by CO_2 laser ablation and their advantages and disadvantages are discussed. The all-glass CLSs possess outstanding heat-dissipating capability and do not require thermal management for up to a few kW of cladding power. Conventionally CLSs are fabricated by utilizing high-index polymer recoating, acid etching or CO_2 laser ablation, etc. CLSs with CO_2 laser ablation are highly preferred in many application due to their chemical free, contamination-free, noncontact manufacturing process. CLSs with CO_2 laser ablated transversal or spiral grooves have the advantages of high efficiency, short processing time. However, the fiber tensile strength is greatly reduced due to glass mini-fractures or cracks that may be introduced and propagate along the grooves. Creating holes on the optical fibers with CO_2 laser ablation is an alternative way to fabricate high efficiency CLSs. It provides greatly improved mechanical strength compared to CLSs with transversal or spiral grooves though it needs longer manufacturing time. In this paper we demonstrate high efficiency CLSs with spiral grooves and holes respectively and their optical, thermal performance and mechanical properties are discussed.