Disclosed is a mode field modifier which can be used in a fiber-to-fiber connector or a source-to-fiber connector. In a downtaper-type mode field modifier embodiment, the modifier comprises a modifier core of refractive index n.sub.1 surrounded by first and second cladding layers having refractive indices...http://www.google.se/patents/US4877300?utm_source=gb-gplus-sharePatent US4877300 - Non-adiabatically-tapered connector
