Side-firing sealing caps for hollow optical fibers

Background and Objectives: Hollow optical fibers are useful for delivery of high-energy infrared laser beam such as Er:YAG lasers. We propose side-firing optics for hollow optical fibers for laser endoscopic applications mainly in oto-rhino-laryngology and urology. Study Design/Materials and Methods: To produce a circular beam, cone-shaped caps are designed and caps with slanted end are proposed for producing a spot beam in side direction. Both types of caps are fabricated by fusing and polished Pyrex and silica glass tubes. Results: For the both of the cone-shaped and slanted-end caps effectively deflect laser beam as designed and these caps show high durability for Er:YAG laser light with pulse energy higher than 100 mJ. Conclusions: By choosing the proper shape of the cap ends, these caps deflect an input laser beam to a preferred direction at low insertion losses. By using these side-firing optics, one can easily irradiate the inside of tubular organs.