Abstract: Aspects of the subject disclosure may include, for example, a process that provides a semiconductor substrate and forms repeating, conductive patterns configured for coupling to active circuitry. Each pattern comprises a group of thermally conductive layers, wherein the group of thermally layers is thermally coupled to a thermal source generated by the active circuitry. Thermally conductive vias interconnect the group of thermally conductive layers, wherein a combination of the vias and the group of thermally conductive layers is configured to transfer heat from the thermal source with a desired directionality. The first repeating patterns are thermally coupled to each other to combine the desired directionality of each of the patterns, wherein the combination results in a distributed directionality of the heat from the thermal source thereby reducing a localized concentration of the heat. Other embodiments are disclosed.

Abstract: A coherent receiver includes a receive signal path including i) an input configured to connect a receive signal, ii) one or more signal paths connected to the input and to one or more optical hybrids, and iii) a variable optical attenuator (VOA) in each of the one or more signal paths; and a local oscillator (LO) signal path including i) an input configured to connect to an LO and the one or more optical hybrids, and ii) one or more complementary VOAs located between the input and the one or more optical hybrids, wherein the one or more complementary VOAs are configured to cancel any phase changes from the VOA in each of the one or more signal paths. The VOA in each of the one or more signal paths and the one or more complementary VOAs can be p-i-n junctions.

Abstract: An avalanche photodiode includes a silicon layer on a substrate; a germanium layer on the silicon layer; a cathode and an anode on any of the silicon layer and the germanium layer; and a plurality of contacts on the germanium layer, in addition to the cathode and the anode. The silicon layer can include a highly doped region at each end, an intrinsic doped region in a middle, and an intermediately doped region between the highly doped region at each end and the intrinsic doped region, and the cathode and the anode are each at a respective a highly doped region at each end. The germanium layer can include a plurality of highly doped regions with each including one of the plurality of contacts.

Abstract: A first photodiode is integrated within at least a first layer of one or more semiconductor layers, the first photodiode comprising an active area optically coupled to a guided mode of a first waveguide to couple the first photodiode to an optical distribution network. One or more associated photodiodes are associated with the first photodiode integrated within at least the first layer in proximity to the first photodiode. An active area of a single associated photodiode or a sum of active areas of multiple associated photodiodes is substantially equal to the active area of the first photodiode. None of the associated photodiodes is coupled to the optical distribution network. Electrical circuitry is configured to generate a signal that represents a difference between (1) a signal derived from the first photodiode and (2) a signal derived from a single associated photodiode or a sum of signals derived from multiple associated photodiodes.

Abstract: The present disclosure provides a multi-pass free-carrier absorption variable optical attenuator device, including: a diode structure including a P-type doped region and an N-type doped region separated by an intrinsic region; and an optical waveguide including a plurality of optical waveguide sections aligned parallel to one another and disposed between the P-type doped region and the N-type doped region and within the intrinsic region of the diode structure. Further, the present disclosure provides a multi-pass thermal phase shifter device, including: a silicon structure including or coupled to one or more heater elements; and an optical waveguide including a plurality of optical waveguide sections aligned parallel to one another and disposed adjacent to the one or more heater elements. Optionally, at least two of the optical waveguide sections have different geometries and are separated by a predetermined gap.

Abstract: Fabricating a photonic integrated circuit includes fabricating structures in one or more silicon layers. At least a first silicon layer comprises: one or more photonic structures, where the photonic structures include one or more waveguides and one or more photodetectors, and one or more light absorbing structures, where at least some of the light absorbing structures include doped silicon. Fabricating the photonic integrated circuit also includes fabricating at least one waveguide in the photonic integrated circuit for receiving light into at least one of the silicon layers.

Abstract: A method and system, in an optical receiver, includes receiving a first photocurrent from a first photodetector and a second photocurrent from a second photodetector; amplifying the first photocurrent with a first amplifier to provide a first output signal and the second photocurrent with a second amplifier to provide a second output signal; adjusting a frequency response of a first path the first photocurrent and a second path of the second photocurrent; and determining a difference between the adjusted first photocurrent and the adjusted second photocurrent.

Abstract: Fabricating a photonic integrated circuit includes fabricating structures in one or more silicon layers. At least a first silicon layer comprises: one or more photonic structures, where the photonic structures include one or more waveguides and one or more photodetectors, and one or more light absorbing structures, where at least some of the light absorbing structures include doped silicon. Fabricating the photonic integrated circuit also includes fabricating at least one waveguide in the photonic integrated circuit for receiving light into at least one of the silicon layers.

Abstract: The present disclosure provides a multi-pass free-carrier absorption variable optical attenuator device, including: a diode structure including a P-type doped region and an N-type doped region separated by an intrinsic region; and an optical waveguide including a plurality of optical waveguide sections aligned parallel to one another and disposed between the P-type doped region and the N-type doped region and within the intrinsic region of the diode structure. Further, the present disclosure provides a multi-pass thermal phase shifter device, including: a silicon structure including or coupled to one or more heater elements; and an optical waveguide including a plurality of optical waveguide sections aligned parallel to one another and disposed adjacent to the one or more heater elements. Optionally, at least two of the optical waveguide sections have different geometries and are separated by a predetermined gap.

Abstract: A method and system, in an optical receiver, includes receiving a first photocurrent from a first photodetector and a second photocurrent from a second photodetector; amplifying the first photocurrent with a first amplifier to provide a first output signal and the second photocurrent with a second amplifier to provide a second output signal; adjusting a frequency response of a first path the first photocurrent and a second path of the second photocurrent; and determining a difference between the adjusted first photocurrent and the adjusted second photocurrent.

Abstract: A method. The method may include transmitting an optical noise signal to a first photodetector and a second photodetector within an optical receiver circuit that includes a transimpedance amplifier circuit. The method may further include measuring, in response to transmitting the optical noise signal, a power output from the optical receiver circuit. The method may further include determining, using the power output, a difference in photodetector responsivity between the first photodetector and the second photodetector. The method may further include adjusting, using a transimpedance gain controller, an amplifier gain within the optical receiver circuit to decrease a difference in photodetector responsivity between the first photodetector and the second photodetector.

Abstract: A method. The method may include transmitting an optical noise signal to a first photodetector and a second photodetector within an optical receiver circuit that includes a transimpedance amplifier circuit. The method may further include measuring, in response to transmitting the optical noise signal, a power output from the optical receiver circuit. The method may further include determining, using the power output, a difference in photodetector responsivity between the first photodetector and the second photodetector. The method may further include adjusting, using a transimpedance gain controller, an amplifier gain within the optical receiver circuit to decrease a difference in photodetector responsivity between the first photodetector and the second photodetector.

Abstract: The invention relates to a variable optical attenuator having a profiled blade. It includes a mounting base with an actuator formed on the base, the actuator carrying the blade which is moveable across a light beam. The blade is profiled so as to provide a predetermined attenuation of the beam as a function of the displacement of the blade, the function being preferably substantially linear. As a way of example, first and second embodiments of the invention describe an electrostatic comb attenuator made of a semiconductor material and forming a monolithic structure. The embodiments relate to different blade profiles, having a protrusion and a notch at the front edge of the blade respectively. The attenuator device additionally includes light input and output lenses for receiving and directing light along a predetermined optical path. Other known type of attenuators having profiled blades, e.g.

Abstract: The invention relates to a variable optical attenuator having a profiled blade. It includes a mounting base with an actuator formed on the base, the actuator carrying the blade which is moveable across a light beam. The blade is profiled so as to provide a predetermined attenuation of the beam as a function of the displacement of the blade, the function being preferably substantially linear. As a way of example, first and second embodiments of the invention describe an electrostatic comb attenuator made of a semiconductor material and forming a monolithic structure. The embodiments relate to different blade profiles, having a protrusion and a notch at the front edge of the blade respectively. The attenuator device additionally includes light input and output lenses for receiving and directing light along a predetermined optical path. Other known type of attenuators having profiled blades, e.g.