Abstract: A flexible endoscope insertion tube having at least one working channel extending in the axial direction of the flexible tube. One or more liners are in coaxial alignment with the distal end working channel of the tube. At least one ceramic tip liner may be disposed on the interior distal end of the endoscope working channel which protects the working channel from operational wear and tear.

Abstract: In an endoscopic system there is a source of radiation and a waveguide, which is symmetric about an axis and receptive of the radiation for guiding the radiation therealong. A coupling mechanism engages or disengages the waveguide to or from an endoscope. An attenuator is deployable in a first position when the waveguide is engaged to the endoscope and deployable in a second position when the waveguide is disengaged from the endoscope. When the attenuator is deployed in the first position, the radiation passes from the waveguide to the endoscope and when the attenuator is in the second position, the radiation is at least partially blocked from passing from the waveguide to the endoscope or from exiting the fiber optic cable.