Specialty Optical Fibers Handbook

generated in the fiber near the coupling plane by filtering out higher order

modes. For similar purposes, copper tubes are used to couple into Er:YAG

fibers.

10.4.1.3 OmniGuide Fiber: Distal End Termination

For surgical applications, where the fiber will encounter a semi-aquatic

environment, precautions are necessary to prevent liquids from entering the

hollow core. For CO

2

fibers, continuous helium flow through the hollow core

is used to solve this problem. To avoid damage to the fiber tip that results from

clogging when in contact with tissue, a short stainless-steel tube is attached to the

end of the fiber, with side holes to aid in gas flow venting. However, not all

applications allow for gas flow through the core. For example, in Er:YAG laser

endoscopic ...