Abstract: An optical transceiver includes optical circuitry disposed on a substrate and comprising a transmitter and a receiver. The circuitry includes least one multi-mode interferometer (MMI), including a multi-mode waveguide comprising an input face and an output face, the input and output faces being bisected by a longitudinal axis, the multi-mode waveguide having a predefined width transverse to the longitudinal axis. Ports are coupled to respective waveguides and are configured to launch one or more input beams through the input face and receive one or more output beams from the output face. The ports include, on at least one of the faces, two or more ports at respective locations that are offset transversely from the longitudinal axis by at least ?0/300 from respective base transverse displacements that are equal to integer fractions of the width.

Abstract: A waveguide assembly includes first and second waveguides. The first waveguide includes silicon, first and second ends, an end member, and a tapered member. The end member extends from the first end. The tapered member extends from the end member to the second end. The second waveguide is optically coupled to and spaced away from the first waveguide. The second waveguide includes silicon nitride, first and second members, and a non-tapered member. The non-tapered member extends from the first member to the second member and in parallel with and opposing the tapered member. An effective refractive index of the non-tapered member matches an effective refractive index of the tapered member at a first plane. The first plane extends through the non-tapered member and the tapered member and perpendicular to a second plane. The second plane extends parallel to a direction of overlap between the first and second waveguides.

Abstract: An optical transceiver includes optical circuitry disposed on a substrate and comprising a transmitter and a receiver. The circuitry includes least one multi-mode interferometer (MMI), including a multi-mode waveguide comprising an input face and an output face, the input and output faces being bisected by a longitudinal axis, the multi-mode waveguide having a predefined width transverse to the longitudinal axis. Ports are coupled to respective waveguides and are configured to launch one or more input beams through the input face and receive one or more output beams from the output face. The ports include, on at least one of the faces, two or more ports at respective locations that are offset transversely from the longitudinal axis by at least ?0/300 from respective base transverse displacements that are equal to integer fractions of the width.