System comprising an integrated waveguide-coupled optically active device and method of formation

A method for forming an integrated-optics system disposed on a first substrate that defines a first plane, the system having a first region, a second region, and a third region, and comprising an optically active device that is optically coupled with a silicon waveguide, the method including:

• forming a coupling waveguide that extends from the first region to the third region, the coupling waveguide including a first layer disposed on a contact layer, the first layer comprising a first compound semiconductor and the contact layer comprising a second compound semiconductor, wherein the coupling waveguide at least partially supports a first optical mode of a light signal;
• forming an optically active device that includes an active-material stack comprising a third compound semiconductor, the active-material stack being disposed on the coupling waveguide to collectively define a composite waveguide that at least partially supports the first optical mode, wherein the optically active device is located only in the first region;
• and
• patterning a silicon layer to define a silicon waveguide in the third region, the silicon waveguide being configured to at least partially support the optical mode, wherein the silicon waveguide is optically coupled with the active-material stack via the coupling waveguide.

An integrated-optics system disposed on a substrate that defines a first plane, the system comprising:

• (1) an optically active device selectively located in a first region of the substrate, wherein the optically active device includes:
• (a) an active-material stack comprising a gain section and a first taper;
• and
• (b) a coupling waveguide that includes a first layer disposed on a contact layer, the first layer comprising a first compound semiconductor and the contact layer comprising a second compound semiconductor, wherein the coupling waveguide at least partially supports a first optical mode of a light signal;
• wherein the active-material stack and the coupling waveguide collectively define a composite waveguide that at least partially supports the first optical mode;
• and
• (2) a silicon layer that includes a silicon waveguide that is selectively located in a second region of the substrate, the silicon waveguide being configured to at least partially support the first optical mode, wherein the silicon layer is configured such that it has a first portion that defines the silicon waveguide, a second portion on which the coupling waveguide is disposed, and a third portion on which the coupling waveguide is not disposed, wherein the second portion and the coupling waveguide collectively provide light confinement in a first direction that is parallel to the first plane, and wherein the third portion confines light in only a second direction that is orthogonal to the first plane;
• and
• wherein the coupling waveguide extends from the first region to a second taper located in the second region, the second taper being configured to optically couple the first optical mode from the composite waveguide into the silicon waveguide.