Mode converter for converting a fraction of one guided mode of an optical signal in an incoming optical waveguide section (A) into another guided mode in an outgoing wave-guiding section (C) by means of a periodic coupling between both guided modes in an intermediate optical waveguide section (B). The...http://www.google.fr/patents/US5185828?utm_source=gb-gplus-shareBrevet US5185828 - Optical waveguide (TE,TM) mode converter
