Abstract: A composite device for splitting photonic functionality across two or more materials comprises a platform, a chip, and a bond securing the chip to the platform. The platform comprises a base layer and a device layer. The device layer comprises silicon and has an opening exposing a portion of the base layer. The chip, a material, comprises an active region (e.g., gain medium for a laser). The chip is bonded to the portion of the base layer exposed by the opening, such that the active region of the chip is aligned with the device layer of the platform.

Abstract: A waveguide coupler includes a first waveguide and a second waveguide. The waveguide coupler also includes a connecting waveguide disposed between the first waveguide and the second waveguide. The connecting waveguide includes a first material having a first index of refraction and a second material having a second index of refraction higher than the first index of refraction.

Abstract: Fabricating a multilevel composite semiconductor structure includes providing a first substrate comprising a first material; dicing a second substrate to provide a plurality of dies; mounting the plurality of dies on a third substrate; joining the first substrate and the third substrate to form a composite structure; and joining a fourth substrate and the composite structure.

Abstract: A composite device for splitting photonic functionality across two or more materials comprises a platform, a chip, and a bond securing the chip to the platform. The platform comprises a base layer and a device layer. The device layer comprises silicon and has an opening exposing a portion of the base layer. The chip, a material, comprises an active region (e.g., gain medium for a laser). The chip is bonded to the portion of the base layer exposed by the opening such that the active region of the chip is aligned with the device layer of the platform. A coating hermetically seals the chip in the platform.

Abstract: A waveguide coupler includes a first waveguide and a second waveguide. The waveguide coupler also includes a connecting waveguide disposed between the first waveguide and the second waveguide. The connecting waveguide includes a first material having a first index of refraction and a second material having a second index of refraction higher than the first index of refraction.

Abstract: A waveguide coupler includes a first waveguide and a second waveguide. The waveguide coupler also includes a connecting waveguide disposed between the first waveguide and the second waveguide. The connecting waveguide includes a first material having a first index of refraction and a second material having a second index of refraction higher than the first index of refraction.

Abstract: A waveguide coupler includes a first waveguide and a second waveguide. The waveguide coupler also includes a connecting waveguide disposed between the first waveguide and the second waveguide. The connecting waveguide includes a first material having a first index of refraction and a second material having a second index of refraction higher than the first index of refraction.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: Fabricating a multilevel composite semiconductor structure includes providing a first substrate comprising a first material; dicing a second substrate to provide a plurality of dies; mounting the plurality of dies on a third substrate; joining the first substrate and the third substrate to form a composite structure; and joining a fourth substrate and the composite structure.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: A method for fabricating a photonic composite device for splitting functionality across materials comprises providing a composite device having a platform and a chip bonded in the platform. The chip is processed comprising patterning, etching, deposition, and/or other processing steps while the chip is bonded to the platform. The chip is used as a gain medium and the platform is at least partially made of silicon.

Abstract: A waveguide mode expander couples a smaller optical mode in a semiconductor waveguide to a larger optical mode in an optical fiber. The waveguide mode expander comprises a shoulder made of crystalline silicon and a ridge made of non-crystalline silicon (e.g., amorphous silicon). In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages have different widths and/or thicknesses at a given cross section.

Abstract: A composite photonic device comprises a platform, a chip, and a contact layer. The platform comprises silicon. The chip is made of a III-V material. The contact layer has indentations to help control a flow of solder during bonding of the platform with the chip. In some embodiments, pedestals are placed under an optical path to prevent solder from flowing between the chip and the platform at the optical path.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: A method of fabricating a composite semiconductor structure includes providing an SOI substrate including a plurality of silicon-based devices, providing a compound semiconductor substrate including a plurality of photonic devices, and dicing the compound semiconductor substrate to provide a plurality of photonic dies. Each die includes one or more of the plurality of photonics devices. The method also includes providing an assembly substrate having a base layer and a device layer including a plurality of CMOS devices, mounting the plurality of photonic dies on predetermined portions of the assembly substrate, and aligning the SOI substrate and the assembly substrate. The method further includes joining the SOI substrate and the assembly substrate to form a composite substrate structure and removing at least the base layer of the assembly substrate from the composite substrate structure.

Abstract: An optical modulator includes an input port, a first waveguide region comprising silicon and optically coupled to the input port, and a waveguide splitter optically coupled to the first waveguide region and having a first output and a second output. The optical modulator also includes a first phase adjustment section optically coupled to the first output and comprising a first III-V diode and a second phase adjustment section optically coupled to the second output and comprising a second III-V diode. The optical modulator further includes a waveguide coupler optically coupled to the first phase adjustment section and the second phase adjustment section, a second waveguide region comprising silicon and optically coupled to the waveguide coupler, and an output port optically coupled to the second waveguide region.

Abstract: A method for fabricating a composite device comprises providing a platform, providing a chip, and bonding the chip to the platform. The platform has a base layer and a device layer above the base layer. An opening in the device layer exposes a portion of the base layer. The chip is bonded to the portion of the base layer exposed by the opening in the device layer. A portion of the chip extends above the platform and is removed.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: A composite device for splitting photonic functionality across two or more materials comprises a platform, a chip, and a bond securing the chip to the platform. The platform comprises a base layer and a device layer. The device layer comprises silicon and has an opening exposing a portion of the base layer. The chip, a material, comprises an active region (e.g., gain medium for a laser). The chip is bonded to the portion of the base layer exposed by the opening such that the active region of the chip is aligned with the device layer of the platform. A coating hermetically seals the chip in the platform.