title: Side-firing germanium oxide optical fibers for use with erbium:YAG laser.
abstract: OBJECTIVE
  During recent experimental studies, the erbium:YAG laser has been shown to be more efficient for lithotripsy and more precise for incision of soft urinary tissues than the conventional holmium:YAG laser. Mid-infrared optical fibers are being developed to allow endoscopic delivery of Er:YAG laser radiation. This paper describes the simple construction and characterization of a side-firing germanium oxide fiber for potential use with the Er:YAG laser in endourology.
  
  
  METHODS
  The 450-microm-core side-firing fibers were constructed from germanium oxide fibers by polishing the distal tip at a 45 degrees angle and placing a protective quartz cap over the tip. The Er:YAG laser radiation, with a wavelength of 2.94 microm, was transmitted through the fibers.
  
  
  CONCLUSIONS
  The fiber transmission rate and damage threshold measured 48 +/- 4% and 149 +/- 37 mJ, respectively (n = 6 fibers). Sufficient pulse energies were transmitted through the side-firing fibers to produce contact tissue ablation.
authors.affiliation: Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Ngo
authors.forename: Nathaniel M
authors.initials: NM
authors.lastname: Fried
mesh_terms: D000535:Aluminum; D004871:Erbium; D005336:Fiber Optic Technology / Q000295:instrumentation / Q000379:methods*; D005857:Germanium; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation; D017602:Lithotripsy, Laser / Q000295:instrumentation / Q000379:methods*; D055100:Optical Fibers; D014545:Urinary Calculi / Q000628:therapy; D013520:Urologic Surgical Procedures / Q000295:instrumentation; D015019:Yttrium
chemical_list: C503779:yttrium-aluminum-garnet; D005857:Germanium; D015019:Yttrium; C040516:germanium oxide; D004871:Erbium; D000535:Aluminum