Abstract: An integrated optical device fabricated in the back end of line process located within the vertical span of the metal stack and having one or more advantages over a corresponding integrated optical device fabricated in the silicon on insulator layer.

Abstract: A composite optical waveguide is constructed using an array of waveguide cores, in which one core is tapered to a larger dimension, so that all the cores are used as a composite input port, and the one larger core is used as an output port. In addition, transverse couplers can be fabricated in a similar fashion. The waveguide cores are preferably made of SiN. In some cases, a layer of SiN which is provided as an etch stop is used as at least one of the waveguide cores. The waveguide cores can be spaced away from a semiconductor layer so as to minimize loses.

Abstract: Two semiconductor chips are optically aligned to form a hybrid semiconductor device. Both chips have optical waveguides and alignment surface positioned at precisely-defined complementary vertical offsets from optical axes of the corresponding waveguides, so that the waveguides are vertically aligned when one of the chips is placed atop the other with their alignment surface abutting each other. The position of the at least one of the alignment surface in a layer stack of its chip is precisely defined by epitaxy. The chips are bonded at offset bonding pads with the alignment surfaces abutting in the absence of bonding material therebetween.

Abstract: A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer is formed of a mode convertor followed by a mode squeezer and a dump waveguide, and may be configured to pass a desired waveguide mode and reject undesired modes. An embodiment is described that transmits a TE0 mode while blocking a TM0 mode by converting it into a higher-order TEn mode in a waveguide taper, squeezing out the TEn mode in a second waveguide taper to lessen its confinement, and then dumping the TEn mode in a waveguide bend that is configured to pass the TE0 mode.

Abstract: A light shield may be formed in photonic integrated circuit between integrated optical devices of the photonic integrated circuit. The light shield may be built by using materials already present in the photonic integrated circuit, for example the light shield may include metal walls and doped semiconductor regions. Light-emitting or light-sensitive integrated optical devices or modules of a photonic integrated circuit may be constructed with light shields integrally built in.

Abstract: A low loss high extinction ratio on-chip polarizer. The polarizer includes an input waveguide taper having an outer waveguiding region that widens in the direction of light propagation along at least a portion of the taper length, and a core waveguiding region that narrows in the direction of light propagation along at least a portion of the taper length, so as to selectively squeeze out light of undesired modes into the outer regions while preserving light of a desired mode in the waveguide core. An output filter section is provided to prevent light from reentering the output waveguide after being squeezed out. An integrated light absorber/deflector may be coupled to the outer waveguiding regions.

Abstract: A compact, low-loss and wavelength insensitive Y-junction for submicron silicon waveguides. The design was performed using FDTD and particle swarm optimization (PSO). The device was fabricated in a 248 nm CMOS line. Measured average insertion loss is 0.28±0.02 dB across an 8-inch wafer. The device footprint is less than 1.2 ?m×2 ?m, orders of magnitude smaller than MMI and directional couplers.

Abstract: A composite optical waveguide is constructed using an array of waveguide cores, in which one core is tapered to a larger dimension, so that all the cores are used as a composite input port, and the one larger core is used as an output port. In addition, transverse couplers can be fabricated in a similar fashion. The waveguide cores are preferably made of SiN. In some cases, a layer of SiN which is provided as an etch stop is used as at least one of the waveguide cores. The waveguide cores can be spaced away from a semiconductor layer so as to minimize loses.

Abstract: An optical device and a method of manufacturing an optical device, including a ridge waveguide second, and a strip-loaded ridge waveguide section, comprises applying two different protective layers and two separate etches at two different depths. The protective layers overlap to protect the same section of the optical device, and to limit the surfaces of optical device to exposure to multiple etches, except at edges where the protective layers overlap.

Abstract: An integrated optical device fabricated in the back end of line process located within the vertical span of the metal stack and having one or more advantages over a corresponding integrated optical device fabricated in the silicon on insulator layer.

Abstract: A temperature-controlled photodetector sub-system is described. The temperature control element allows the operation of the photodetector at a desired temperature. The temperature control element can be a heater or a cooler. In some cases, the photodetector is a germanium photodetector. In some cases a temperature measuring device is provided. In some cases, a control circuit is used to control the temperature of the germanium photodetector within a temperature range, or at a temperature of interest. An advantage provided by the apparatus described is the operation of the photodetector so that the responsivity of the germanium detector can be held at essentially a constant value.

Abstract: An integrated optical device fabricated in the back end of line process located within the vertical span of the metal stack and having one or more advantages over a corresponding integrated optical device fabricated in the silicon on insulator layer.

Abstract: A compact, low-loss and wavelength insensitive Y-junction for submicron silicon waveguides. The design was performed using FDTD and particle swarm optimization (PSO). The device was fabricated in a 248 nm CMOS line. Measured average insertion loss is 0.28±0.02 dB across an 8-inch wafer. The device footprint is less than 1.2 ?m×2 ?m, orders of magnitude smaller than MMI and directional couplers.

Abstract: Two semiconductor chips are optically aligned to form a hybrid semiconductor device. Both chips have optical waveguides and alignment surface positioned at precisely-defined complementary vertical offsets from optical axes of the corresponding waveguides, so that the waveguides are vertically aligned when one of the chips is placed atop the other with their alignment surface abutting each other. The position of the at least one of the alignment surface in a layer stack of its chip is precisely defined by epitaxy. The chips are bonded at offset bonding pads with the alignment surfaces abutting in the absence of bonding material therebetween.

Abstract: A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer includes an input waveguide taper having an outer waveguiding region that widens in the direction of light propagation along at least a portion of the taper length, and a core waveguiding region that narrows in the direction of light propagation along at least a portion of the taper length, so as to selectively squeeze out light of undesired modes into the outer regions while preserving light of a desired mode in the waveguide core. An integrated light absorber/deflector may be coupled to the outer waveguiding regions.

Abstract: A composite optical waveguide is constructed using an array of waveguide cores, in which one core is tapered to a larger dimension, so that all the cores are used as a composite input port, and the one larger core is used as an output port. In addition, transverse couplers can be fabricated in a similar fashion. The waveguide cores are preferably made of SiN. In some cases, a layer of SiN which is provided as an etch stop is used as at least one of the waveguide cores. The waveguide cores can be spaced away from a semiconductor layer so as to minimize loses.

Abstract: A temperature-controlled photodetector sub-system is described. The temperature control element allows the operation of the photodetector at a desired temperature. The temperature control element can be a heater or a cooler. In some cases, the photodetector is a germanium photodetector. In some cases a temperature measuring device is provided. In some cases, a control circuit is used to control the temperature of the germanium photodetector within a temperature range, or at a temperature of interest. An advantage provided by the apparatus described is the operation of the photodetector so that the responsivity of the germanium detector can be held at essentially a constant value.

Abstract: An integrated optical device fabricated in the back end of line process located within the vertical span of the metal stack and having one or more advantages over a corresponding integrated optical device fabricated in the silicon on insulator layer.

Abstract: A compact, low-loss and wavelength insensitive Y-junction for submicron silicon waveguides. The design was performed using FDTD and particle swarm optimization (PSO). The device was fabricated in a 248 nm CMOS line. Measured average insertion loss is 0.28±0.02 dB across an 8-inch wafer. The device footprint is less than 1.2 ?m×2 ?m, orders of magnitude smaller than MMI and directional couplers.

Abstract: A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer is formed of a mode convertor followed by a mode squeezer and a dump waveguide, and may be configured to pass a desired waveguide mode and reject undesired modes. An embodiment is described that transmits a TE0 mode while blocking a TM0 mode by converting it into a higher-order TEn mode in a waveguide taper, squeezing out the TEn mode in a second waveguide taper to lessen its confinement, and then dumping the TEn mode in a waveguide bend that is configured to pass the TE0 mode.