On-chip tunable multi-mode interference reflector

The invention relates to an on-chip tunable multimode interference reflector. The reflector comprises a substrate, a device layer arranged on the substrate and a protection layer on the device layer,wherein a dual-port multimode interference reflector and an electrode are formed in the device layer, the electrode is a micro heating electrode or a current injection electrode, the dual-port multimode interference reflector comprises input waveguide , first tapered waveguide, multimode waveguide, a reflection area connected with the multimode waveguide, second tapered waveguide and output waveguide, the input waveguide is connected with the multimode waveguide through the first tapered waveguide, the output waveguide is connected with the multimode waveguide through the second tapered waveguide, and the electrode is located in the multimode waveguide and/or the reflection area. The on-chip tunable multimode interference reflector has the advantages of being small in size, low in loss, low in cost, easy to integrate and the like, is compatible with the traditional semiconductor photoelectron technology and CMOS technology and has a wide application prospect in the field of photonic integrated chips.