Mid-IR Germanium Oxide Fibers for Contact Erbium Laser Tissue Ablation in Endoscopic Surgery

Endoscopic surgical applications of erbium lasers have been limited due to the lack of a suitable mid-IR optical fiber delivery system. Germanium oxide fibers are used for noncontact tissue ablation, but are not recommended for contact tissue ablation applications typically required during endoscopic surgery. 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 45deg angled tips or micromirrors. Average powers up to 8.5 W (850 mJ at 10 Hz) and transmission up to 70% was demonstrated through 450-mum-core, 1.5-m-long fibers, sufficient for endoscopic laser ablation of soft and hard tissues in contact mode.