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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.

Previous studies reported difficulty emulsifying hard cataracts with Erbium:YAG laser. This preliminary ex vivo tissue study demonstrates successful Er:YAG laser emulsification of Grade 4+ cataracts using a germanium oxide / sapphire optical fiber delivery system.

Endoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. This study compares the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica or sapphire fiber tips for potential use in endoscopic tissue ablation. Er:YAG laser radiation with a wavelength of 2.94 mm, pulse length of 300 ms, pulse energies of 5-1360 mJ, and pulse rates of 3-10 Hz, was delivered through 1-m-long germanium oxide fibers with either 1-cm-long, 550-mm-diameter silica or sapphire tips. Transmission through the germanium oxide / sapphire fibers measured 65 + 5 % compared with 55 + 4 % for the germanium oxide / silica fibers (P < 0.05). The damage threshold for the hybrid fibers averaged 309 + 44 mJ and 126 + 43 mJ, respectively (n = 7 fibers each) (P < 0.05). Maximum pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively. Improved index-matching of the trunk fiber and fiber tip at 2.94 mm resulted in higher transmission and damage thresholds for the germanium oxide / sapphire fibers. The germanium oxide / sapphire fiber may represent a promising mid-IR optical fiber delivery system for use in endoscopic applications of the Er:YAG laser requiring a flexible, biocompatible, and robust fiber delivery system for contact tissue ablation.

Background and Objectives Endoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. The purpose of this study was to compare the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica and sapphire fiber tips for potential use in contact tissue ablation during endoscopy. Study Design/Materials and Methods Er:YAG laser radiation with a wavelength of 2.94 µm, pulse length of 300 microseconds, pulse energies from 5 to 1,360 mJ, coupled into pulse repetition rates of 3–10 Hz, was through 1-m-long germanium oxide fibers with either 1-cm-long, 550-µm-diameter silica or sapphire tips. Results Transmission through the germanium oxide/sapphire fibers measured 65±5% compared with 55±4% for the germanium oxide/silica fibers (P