Mode converter having multi-layer structure and optical branching device

摘要: The invention discloses a mode converter having multi-layer structure and an optical branching device. comprises flat waveguides at least three layers of ridge which are arranged on the waveguide, wherein width each layer is gradually decreased from input end to output end; when certain value, cut off, namely one reduced, so that height reduced gradually; farther away cut-off position waveguides; consists single-layer waveguides. A transverse free propagation area device without limitation. Compared with prior art, technology provided by has advantages that: efficiency coupling fibres can be improved, one-step etching process stability transmission in improved same time.