Patent ID: 7961994

Claim:
An optical device, comprising: a first waveguide having an end portion configured to receive an optical signal, the optical signal having a fundamental mode, the first waveguide including a first material; a second waveguide having an end portion, the second waveguide including a second material; a gap including a third material different than the first and second materials, the end portion of the first waveguide being separated from the end portion of the second waveguide by the gap, such that the end portion of the second waveguide supplies the optical signal to the end portion of the first waveguide via the gap, where the first waveguide is configured such that the optical signal undergoes multimode interference to focus the fundamental mode at the end portion of the second waveguide; a cladding layer; a lower reflector; a low index multimode interference layer formed above the lower reflector; and an upper reflector formed above the low index multimode interference region.