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 and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: Micro pillars are formed in silicon. The micro pillars are used in boding the silicon to hetero-material such as III-V material, ceramics, or metals. In bonding the silicon to the hetero-material, indium is used as a bonding material and attached to the hetero-material. The bonding material is heated and the silicon and the hetero-material are pressed together. As the silicon and the hetero-material are pressed together, the micro pillars puncture the bonding material. In some embodiments, pedestals are used in the silicon as hard stops to align the hetero-material with the silicon.

Abstract: A composite semiconductor laser is made by securing a III-V wafer to a transfer wafer. A substrate of the III-V wafer is removed, and the III-V wafer is etched into a plurality of chips while the III-V wafer is secured to the transfer wafer. The transfer wafer is singulated. A portion of the transfer wafer is used as a handle for bonding the chip in a recess of a silicon device. The chip is used as a gain medium for the semiconductor laser.

Abstract: A photonic device includes a semiconductor wafer having a waveguide formed therein. An end of the waveguide includes a step. The photonic device further includes a semiconductor chip bonded to the semiconductor wafer and having an active region, and a waveguide coupler disposed in a gap between a sidewall of the semiconductor chip and the end of the waveguide. The waveguide coupler includes an optical bridge that has a first end and a second end opposing the first end. The first end of the optical bridge is interfaced with a facet of the active region of the semiconductor chip. The second end of the optical bridge is interfaced with the end of waveguide, and has a portion thereof disposed over the step at the end of the waveguide.

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 and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: A method of fabricating a waveguide mode expander includes providing a substrate including a waveguide, bonding a chiplet including multiple optical material layers in a mounting region adjacent an output end of the waveguide, and selectively removing portions of the chiplet to form tapered stages that successively increase in number and lateral size from a proximal end to a distal end of the chiplet. The first optical material layer supports an input mode substantially the same size as a mode exiting the waveguide. One or more of the overlying layers, when combined with the first layer, support a larger, output optical mode size. Each tapered stage of the mode expander is formed of a portion of a respective layer of the chiplet. The first layer and the tapered stages form a waveguide mode expander that expands an optical mode of light traversing the chiplet.

Abstract: A method forms a vertical output coupler for a waveguide, formed of waveguide material and disposed within a layer stack on a top surface of a wafer. The method includes etching through a portion of the wafer to form a via that exposes the waveguide material, and etching the waveguide material to remove at least a first portion of the waveguide. The etching forms a tilted plane in the waveguide material. The method further includes coating the first tilted plane with one or more reflective layers, to form a tilted mirror in contact with the first tilted plane in the waveguide material. The tilted mirror forms the vertical output coupler such that light propagating through the waveguide is deflected by the tilted mirror, and exits the waveguide.

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 and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: A transfer substrate with a compliant resin is used to bond one or more chips to a target wafer. An implant region is formed in a transfer substrate. A portion of the transfer substrate is etched to form a riser. Compliant material is applied to the transfer substrate. A chip is secured to the compliant material, wherein the chip is secured to the compliant material above the riser. The chip is bonded to a target wafer while the chip is secured to the compliant material. The transfer substrate and compliant material are removed from the chip. The transfer substrate is opaque to UV light.

Abstract: A method of fabricating a waveguide mode expander includes providing a substrate including a waveguide, bonding a chiplet including multiple optical material layers in a mounting region adjacent an output end of the waveguide, and selectively removing portions of the chiplet to form tapered stages that successively increase in number and lateral size from a proximal end to a distal end of the chiplet. The first optical material layer supports an input mode substantially the same size as a mode exiting the waveguide. One or more of the overlying layers, when combined with the first layer, support a larger, output optical mode size. Each tapered stage of the mode expander is formed of a portion of a respective layer of the chiplet. The first layer and the tapered stages form a waveguide mode expander that expands an optical mode of light traversing the chiplet.

Abstract: A widely tunable laser system includes a substrate, first and second lasers, an output and at least one optical combining device. The first laser is integrated with the substrate, includes a gain medium that includes a first material, and emits light at a wavelength that is tunable within a first wavelength range that is determined at least in part by the first material. The second laser is integrated with the substrate, includes a gain medium that includes a second material, and emits light at a wavelength that is tunable within a second wavelength range that is different from the first wavelength range that is determined at least in part by the second material. The at least one optical combining device is configured to direct light from one or both of the first laser and the second laser to the output.

Abstract: A modulator and a capacitor are integrated on a semiconductor substrate for modulating a laser beam. Integrating the capacitor on the substrate reduces parasitic inductance for high-speed optical communication.

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 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 and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: A method forms a vertical output coupler for a waveguide that propagates light along a horizontal propagation direction, through a waveguide material that overlies a buried oxide layer. The method includes etching the waveguide to remove a portion of the waveguide. The etching forms at least a first plane that is at an edge of the waveguide, is adjacent to the removed portion of the waveguide, and is tilted at a vertical angle between 20 degrees and 70 degrees with respect to the propagation direction. The method further includes coating the first tilted plane with a reflective metal to form a mirror, such that the mirror reflects the light into a direction having a vertical component.

Abstract: A composite semiconductor laser is made by securing a III-V wafer to a transfer wafer. A substrate of the III-V wafer is removed, and the III-V wafer is etched into a plurality of chips while the III-V wafer is secured to the transfer wafer. The transfer wafer is singulated. A portion of the transfer wafer is used as a handle for bonding the chip in a recess of a silicon device. The chip is used as a gain medium for the semiconductor laser.

Abstract: A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.

Abstract: A photonic device includes a semiconductor wafer having a waveguide formed therein. An end of the waveguide includes a step. The photonic device further includes a semiconductor chip bonded to the semiconductor wafer and having an active region, and a waveguide coupler disposed in a gap between a sidewall of the semiconductor chip and the end of the waveguide. The waveguide coupler includes an optical bridge that has a first end and a second end opposing the first end. The first end of the optical bridge is interfaced with a facet of the active region of the semiconductor chip. The second end of the optical bridge is interfaced with the end of waveguide, and has a portion thereof disposed over the step at the end of the waveguide.

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 and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: A widely tunable laser system includes a substrate, first and second lasers, an output and at least one optical combining device. The first laser is integrated with the substrate, includes a gain medium that includes a first material, and emits light at a wavelength that is tunable within a first wavelength range that is determined at least in part by the first material. The second laser is integrated with the substrate, includes a gain medium that includes a second material, and emits light at a wavelength that is tunable within a second wavelength range that is different from the first wavelength range that is determined at least in part by the second material. The at least one optical combining device is configured to direct light from one or both of the first laser and the second laser to the output.