Optical coupling and mode-selective separation or superposition of light fields

The invention relates to a device for light coupling and for mode-selective separation or superposition of a light field, to the use thereof and to a method for producing a waveguide-based light coupling element (10) which is designed for mode-selective separation or superposition of a light field at a further light coupling point (410) of an optical component (400). The device comprises at least one waveguide-based optical coupling element (10) having at least three optical coupling points (100, 370, 380), and at least one optical assembly (400) having at least one further optical coupling point (410) wherein the at least one optical coupling point (100, 370, 380) is optically connected to the at least one further optical coupling point (410), and wherein the waveguide-based optical coupling element (10) is designed to efficiently and bidirectionally transmit light between the eigenmodes (120, 260) associated with the first optical coupling point (100) and the second optical coupling point (370) and between