A germanium waveguide is formed from a P-type silicon substrate that is coated with a heavily-doped N-type germanium layer and a first N-type doped silicon layer. Trenches are etched into the silicon substrate to form a stack of a substrate strip, a germanium strip, and a first silicon strip. This structure is then coated with a silicon nitride layer.

A photonic integrated circuit platform includes a substrate, a first oxide layer disposed on the substrate and including an insulating transparent oxide, and a first optical element layer disposed on the first oxide layer and including a semiconductor material. The photonic integrated circuit platform further includes a second optical element layer disposed on the first optical element layer and including an insulating material different from the insulating transparent oxide of the first oxide layer, the second optical element layer further including a compound semiconductor material different from the semiconductor material of the first optical element layer, a second oxide layer disposed on the second optical element layer and including an insulating transparent oxide, and a plurality of optical elements formed by patterning the first optical element layer or the second optical element layer.

An exemplary multi quantum well structure may include a silicon platform having a pit formed in the silicon platform, a chip positioned inside the pit, a first waveguide formed in the chip, and a second waveguide formed in the silicon platform. The pit may be defined at least in part by a sidewall and a base. The chip may include a first side and a first recess in the first side. The first side may be defined in part by a first cleaved or diced facet. The first recess may be defined in part by a first etched facet. The first waveguide may be configured to guide an optical beam to pass through the first etched facet. The second waveguide may be configured to guide the optical beam to pass through the sidewall. The second waveguide may be optically aligned with the first waveguide.

A device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure supporting a first optical mode and at least one of the modal gain control structures. The second element comprises a passive waveguide structure supporting a second optical mode. The third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes. If the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitate efficient adiabatic transformation between the second optical mode and one of the intermediate optical modes. No adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks.

A method of manufacturing an optoelectronic device. The manufactured device includes a photonic component coupled to a waveguide. The method comprising: providing a device coupon, the device coupon including the photonic component; providing a silicon platform, the silicon platform comprising a cavity within which is a bonding surface for the device coupon; transfer printing the device coupon onto the cavity, such that a surface of the device coupon directly abuts the bonding surface and at least one channel is present between the device coupon and a sidewall of the cavity; and filling the at least one channel with a filling material via a spin-coating process, to form a bridge coupling the III-V semiconductor based photonic component to the silicon waveguide.

A germanium waveguide is formed from a P-type silicon substrate that is coated with a heavily-doped N-type germanium layer and a first N-type doped silicon layer. Trenches are etched into the silicon substrate to form a stack of a substrate strip, a germanium strip, and a first silicon strip. This structure is then coated with a silicon nitride layer.

A method of manufacturing an electro-optically active device. The method comprising the steps of: etching a cavity on a silicon-on-insulator wafer; providing a sacrificial layer adjacent to a substrate of a lll-V semiconductor wafer; epitaxially growing an electro-optically active structure on the lll-V semiconductor wafer; etching the epitaxially grown optically active structure into an electro-optically active mesa; disposing the electro-optically active mesa in the cavity of the silicon-on-insulator wafer and bonding a surface of the electro-optically active mesa, which is distal to the sacrificial layer, to a bed of the cavity; and removing the sacrificial layer between the substrate of the lll-V semiconductor wafer and the electro-optically active mesa.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A photonic integrated circuit platform includes a substrate, a first oxide layer disposed on the substrate and including an insulating transparent oxide, and a first optical element layer disposed on the first oxide layer and including a semiconductor material. The photonic integrated circuit platform further includes a second optical element layer disposed on the first optical element layer and including an insulating material different from the insulating transparent oxide of the first oxide layer, the second optical element layer further including a compound semiconductor material different from the semiconductor material of the first optical element layer, a second oxide layer disposed on the second optical element layer and including an insulating transparent oxide, and a plurality of optical elements formed by patterning the first optical element layer or the second optical element layer.