https://www.photonstream.com/products/end-cap-fiber/
Fiber end cap is a small piece of coreless quartz, which was spliced to the fiber tip to reduce the light intensity at the air-to-glass interface.
Elliot Jensen and Elliot Fintry have a lot in common. They share the same name, the same house, the same school, oh and they hate each other but, as they will quickly learn, there is a fine line between love and hate.