Abstract: An integrated circuit can include one or more photonic layers that include a plurality of photonic integrated circuit portions. A first optical coupler is configured to couple an optical mode of an optical wave to a first photonic integrated circuit portion in the one or more photonic layers. A second optical coupler is configured to couple an optical mode of an optical wave to a second photonic integrated circuit portion that is optically uncoupled to the first photonic integrated circuit portion. The second photonic integrated circuit portion comprises a polarization-sensitive photonic component, and an optical splitter comprising at least one input port optically coupled to the polarization-sensitive photonic component and at least two output ports including a first output port and a second output port.

Abstract: An optical modulator includes a first Radio Frequency (RF) line and a second RF line; an optical waveguide along a length of the modulator with an input and an output; and a plurality of segments along the length including a first set of segments, a single RF line crossing, and a second set of segments, wherein the first set of segments and the second set of segments have an inversion of their respective orientation at the RF line crossing, and wherein the RF line crossing is located off center relative to the plurality of segments, wherein each of the first RF line and the second RF line extend along the length and cross one another at the RF line crossing.

Abstract: An optical modulator includes a first Radio Frequency (RF) line and a second RF line; an optical waveguide along a length of the modulator with an input and an output; and a plurality of segments along the length including a first set of segments, a single RF line crossing, and a second set of segments, wherein the first set of segments and the second set of segments have an inversion of their respective orientation at the RF line crossing, and wherein the RF line crossing is located off center relative to the plurality of segments, wherein each of the first RF line and the second RF line extend along the length and cross one another at the RF line crossing.

Abstract: An integrated circuit comprises: at least one photonic layer that includes one or more optical waveguides; a first optical coupler that couples at least a first optical mode outside of the photonic layer to a first waveguide in the photonic layer; a photonic device that includes one or more ports in the photonic layer; a first multi-port optical coupler that includes three or more ports in the photonic layer, including a first port optically coupled to the first optical coupler, a second port optically coupled to a first port of the photonic device, and a third port optically coupled to a first optical reflector configured to send substantially all optical power emitted from the third port of the first multi-port optical coupler back to the third port of the first multi-port optical coupler.

Abstract: An integrated circuit comprises: at least one photonic layer that includes one or more optical waveguides; a first optical coupler that couples at least a first optical mode outside of the photonic layer to a first waveguide in the photonic layer; a photonic device that includes one or more ports in the photonic layer; a first multi-port optical coupler that includes three or more ports in the photonic layer, including a first port optically coupled to the first optical coupler, a second port optically coupled to a first port of the photonic device, and a third port optically coupled to a first optical reflector configured to send substantially all optical power emitted from the third port of the first multi-port optical coupler back to the third port of the first multi-port optical coupler.

Abstract: An optical modulator includes multiple segments including modulator segments and a Radio Frequency (RF) crossing segment where RF lines extending a length of the modulator cross one another. The present disclosure includes optimization of one or more of a geometry of the RF crossing and a location of the RF crossing segment along the length. The geometry is selected so that the RF crossing segment appears as another segment having similar characteristics as modulator segments. The location of the RF crossing segment is selected to balance out fabrication error and phase efficiency.

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: An integrated circuit comprises: at least one photonic layer that includes one or more optical waveguides; a first optical coupler that couples at least a first optical mode outside of the photonic layer to a first waveguide in the photonic layer; a photonic device that includes one or more ports in the photonic layer; a first multi-port optical coupler that includes three or more ports in the photonic layer, including a first port optically coupled to the first optical coupler, a second port optically coupled to a first port of the photonic device, and a third port optically coupled to a first optical reflector configured to send substantially all optical power emitted from the third port of the first multi-port optical coupler back to the third port of the first multi-port optical coupler.

Abstract: One or more photonic structures are formed within one or more layers over a surface of a substrate, and multiple trenches are formed through the one or more layers housing devices coupled to one or more of the photonic structures. The trenches may include: a first trench that has a bottom surface within the substrate that has a first surface topology characterized by a first surface roughness at a first depth within the substrate relative to the surface of the substrate, and a second trench that has a bottom surface within the substrate that has a second surface topology characterized by a second surface roughness at a second depth within the substrate relative to the surface of the substrate. The first surface roughness may be greater than the second surface roughness, and the second depth may be greater than the first depth.

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: 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: An optical modulator includes multiple segments including modulator segments and a Radio Frequency (RF) crossing segment where RF lines extending a length of the modulator cross one another. The present disclosure includes optimization of one or more of a geometry of the RF crossing and a location of the RF crossing segment along the length. The geometry is selected so that the RF crossing segment appears as another segment having similar characteristics as modulator segments. The location of the RF crossing segment is selected to balance out fabrication error and phase efficiency.

Abstract: A photodetector circuit is disclosed. The photodetector circuit includes an optical input configured to receive a source optical signal for detection by the photodetector circuit, an optical waveguide for coupling the optical input and at least one side of a plurality of sides of a photodiode, wherein the optical waveguide is configured to generate a first optical signal and a second optical signal from the source optical signal, and the photodiode coupled to the first optical waveguide, where the photodiode is illuminated on the at least one side by the first and second optical signals at different locations on the photodiode, where the photodiode generates a photocurrent based on the first and second optical signals reducing photocurrent saturation. Providing a delay between the first and second optical signals reduces an out-of-band frequency response of the photodiode circuit.

Abstract: An optical modulator includes a first arm and a second arm, each arm includes an arrangement with an equal amount of p-doped material and an equal amount of n-doped material, such that mask misalignment causes a same effect in both arms; and each arm includes a plurality of segments where electrodes connect for push-pull operation of the first arm and the second arm.

Abstract: A spot-size converter includes a first part of a waveguiding structure to couple to a first waveguide to receive light from or transmit light to the first waveguide in a first propagation mode, wherein the first part of the waveguiding structure has a lower waveguiding structure with a varying effective refractive index that decreases away from the first waveguide; and a second part of the waveguiding structure to couple to a second waveguide to transmit light to or receive light from the second waveguide in a second propagation mode, the second part of the waveguiding structure includes an upper waveguiding structure with a plurality of high-index elements arranged therein, an overlap region is between the first part and the second part, the first propagation mode progressively transforms into the second propagation mode in the overlap region.

Abstract: An optical modulator includes a first arm and a second arm, each arm includes an arrangement with an equal amount of p-doped material and an equal amount of n-doped material, such that mask misalignment causes a same effect in both arms; and each arm includes a plurality of segments where electrodes connect for push-pull operation of the first arm and the second arm.

Abstract: A photodetector circuit is disclosed. The photodetector circuit includes an optical input configured to receive a source optical signal for detection by the photodetector circuit, an optical waveguide for coupling the optical input and at least one side of a plurality of sides of a photodiode, wherein the optical waveguide is configured to generate a first optical signal and a second optical signal from the source optical signal, and the photodiode coupled to the first optical waveguide, where the photodiode is illuminated on the at least one side by the first and second optical signals at different locations on the photodiode, where the photodiode generates a photocurrent based on the first and second optical signals reducing photocurrent saturation. Providing a delay between the first and second optical signals reduces an out-of-band frequency response of the photodiode circuit.

Abstract: A spot-size converter includes a first part of a waveguiding structure to couple to a first waveguide to receive light from or transmit light to the first waveguide in a first propagation mode, wherein the first part of the waveguiding structure has a lower waveguiding structure with a varying effective refractive index that decreases away from the first waveguide; and a second part of the waveguiding structure to couple to a second waveguide to transmit light to or receive light from the second waveguide in a second propagation mode, the second part of the waveguiding structure includes an upper waveguiding structure with a plurality of high-index elements arranged therein, an overlap region is between the first part and the second part, the first propagation mode progressively transforms into the second propagation mode in the overlap region.

Abstract: A spot-size converter having a waveguiding structure. The first part of the waveguiding structure receives light from or transmits light to a first waveguide in a first propagation mode. The first part of the waveguiding structure has a longitudinally varying effective refractive index that decreases away from the first waveguide. The second part of the waveguiding structure transmits light to or receives light from a second waveguide in a second propagation mode. The second part of the waveguiding structure has a number of high-index elements arranged in a single plane, extending along a longitudinal waveguiding axis and at least partially overlapping the first part of the waveguiding structure. The first propagation mode of the first waveguide progressively transforms into the second propagation mode of the second waveguide along the longitudinal waveguiding axis through an overlap region between the first part and the second part of the waveguiding structure.

Abstract: An optoelectronic integrated circuit includes (i) a first back-to-back-junction component (BBJC) and a second BBJC that conform to a first fabrication pattern, where the first BBJC includes a first A-type p-n junction (APNJ) in series with a first B-type p-n junction (BPNJ), where the second BBJC includes a second APNJ in series with a second BPNJ, and (ii) an optical component conforming to a second fabrication pattern that superimposes the first fabrication pattern. The APNJs and BPNJs may be identified based overlapping with separate arms of the optical component. The optical component overlaps the APNJs and BPNJs to provide modulation to optical signals using the modulation voltage from the electrodes. The first APNJ, the first BPNJ, the second APNJ, and the second BPNJ are disposed along respective directions, where metal bridges may be used, to reduce an imbalance in the modulation of the optical signals resulting from a fabrication misalignment.