Comparison of germanium oxide fibers with silica and sapphire fiber tips for transmission of erbium: YAG laser radiation

✍ Scribed by Travis J. Polletto; Anthony K. Ngo; Alexei Tchapyjnikov; Ken Levin; Danh Tran; Nathaniel M. Fried

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 70 KB
• Volume: 38
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.20382

✦ Synopsis

Abstract

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<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). The highest pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively.

Conclusions

Improved index‐matching of the trunk fiber and fiber tip at 2.94 µm resulted in higher transmission and damage thresholds for the germanium oxide/sapphire fibers. The germanium oxide/sapphire fiber may represent a promising mid‐infrared 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. Lasers Surg. Med. 38:787–791, 2006. © 2006 Wiley‐Liss, Inc.