Mid-IR Germanium Oxide Fibers for Erbium:YAG and Erbium:YSGG Contact Laser Tissue Ablation in Endourology

Endoscopic surgical applications of Erbium:YAG and Erbium:YSGG lasers have been limited due to the lack of a suitable mid-IR optical fiber delivery system. Germanium oxide fibers are currently used in the clinic for non-contact tissue ablation, but are not recommended for contact tissue ablation applications typically required during endoscopic surgery in a fluid environment. This study describes the assembly and characterization of hybrid mid-IR fibers consisting of germanium oxide trunk fibers and sapphire fiber tips, and side-firing germanium oxide fibers with either 45° angled fiber tips or micro-mirrors. Average powers up to 8.5 W (850 mJ at 10 Hz) and transmission up to 70% was demonstrated through 450-μm-core, 1.5-meter-long fibers, sufficient for endoscopic laser ablation of soft and hard tissues in contact mode.