Compact 3-dB tapered multimode interference coupler in silicon-on-insulator.

We have fabricated a compact 3-dB multimode interference coupler with a large silicon-on-insulator cross section. To reduce the length of the usual symmetric interference multimode interference coupler, we propose using a parabolically tapered structure. The length of the device is 398microm . The device has a uniformity of 0.28 dB.