Abstract: An optical modulator includes a waveguide core; a first transition zone located between a first side of the waveguide core and a first electrical contact region; and a second transition zone located between a second side of the waveguide core and a second electrical contact region, wherein one or more of the first transition zone and second transition zone has a variable thickness. The variable thickness is confined to the one or more of the first transition zone and second transition zone. The variable thickness removes a portion of the highly doped first transition zone and the highly doped second transition zone thereby reducing contact resistance.

Abstract: A silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of either optical attenuation or contact access resistance or both. A silicon-based modulator includes a waveguide including a contact region and a core region, wherein the waveguide includes a dopant concentration that decreases from the contact region to the core region in a transition zone according to a doping profile that is variable.

Abstract: An optical modulator includes a rib; and a slab interconnected to both sides of the rib; wherein the rib is dimensioned relative to the slab to support guiding of a Transverse Magnetic (TM) mode with a main lobe that propagates orthogonal to the slab and with the main lobe substantially excluded from the slab. The rib guides wavelengths in an infrared range in the TM mode. A height of the rib, relative to the slab, is about half of a width of the rib, between the slab.

Abstract: A silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of optical attenuation or contact access resistance or both. A modulator includes a core; a first transition zone that is a P-side region adjacent to the waveguide core, the first transition zone has a first longitudinal doping profile; and a second transition zone that is an N-side region adjacent to the core on an opposite side as the first transition region, the second transition zone has a second longitudinal doping profile; the first longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the first transition region to mimic a first lateral doping profile, and the second longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the second transition region to mimic a second lateral doping profile.

Abstract: A silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of either optical attenuation or contact access resistance or both. A silicon-based modulator includes a waveguide including a contact region and a core region, wherein the waveguide includes a dopant concentration that decreases from the contact region to the core region in a transition zone according to a doping profile that is variable.

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: An optical modulator includes a rib; and a slab interconnected to both sides of the rib; wherein the rib is dimensioned relative to the slab to support guiding of a Transverse Magnetic (TM) mode with a main lobe that propagates orthogonal to the slab and with the main lobe substantially excluded from the slab. The rib guides wavelengths in an infrared range in the TM mode. A height of the rib, relative to the slab, is about half of a width of the rib, between the slab.

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 silicon photonics modulator includes a rib that is a PN junction; a slab including a P doped region adjacent to the waveguide core on a first side and an N doped region adjacent to the waveguide core on a second side, opposite the first side; and a first electrode connected to the P-doped region and a second electrode connected to the N-doped region, wherein the rib is dimensioned to support guiding of a Transverse Magnetic (TM) mode with a main lobe that propagates orthogonal to the slab. The rib guides wavelengths in an infrared range in the TM mode.

Abstract: A silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of either optical attenuation or contact access resistance or both. A silicon-based modulator includes a waveguide core that is a PN junction region; a first transition zone that is a P-side region adjacent to the waveguide core and a first electrode; and a second transition zone that is an N-side region adjacent to the waveguide core on an opposite side as the first transition region and a second electrode; wherein a thickness of each of the first transition zone and the second transition zone is variable in any of a lateral direction, a longitudinal direction, and both the lateral direction and the longitudinal direction, each of the lateral direction and the longitudinal direction are relative to the waveguide core.

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 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 silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of optical attenuation or contact access resistance or both. A modulator includes a core; a first transition zone that is a P-side region adjacent to the waveguide core, the first transition zone has a first longitudinal doping profile; and a second transition zone that is an N-side region adjacent to the core on an opposite side as the first transition region, the second transition zone has a second longitudinal doping profile; the first longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the first transition region to mimic a first lateral doping profile, and the second longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the second transition region to mimic a second lateral doping profile.

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 silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of either optical attenuation or contact access resistance or both. A silicon-based modulator includes a waveguide core that is a PN junction region; a first transition zone that is a P-side region adjacent to the waveguide core and a first electrode; and a second transition zone that is an N-side region adjacent to the waveguide core on an opposite side as the first transition region and a second electrode; wherein a thickness of each of the first transition zone and the second transition zone is variable in any of a lateral direction, a longitudinal direction, and both the lateral direction and the longitudinal direction, each of the lateral direction and the longitudinal direction are relative to the waveguide core.

Abstract: A silicon photonics modulator includes a rib that is a PN junction; a slab including a P doped region adjacent to the waveguide core on a first side and an N doped region adjacent to the waveguide core on a second side, opposite the first side; and a first electrode connected to the P-doped region and a second electrode connected to the N-doped region, wherein the rib is dimensioned to support guiding of a Transverse Magnetic (TM) mode with a main lobe that propagates orthogonal to the slab. The rib guides wavelengths in an infrared range in the TM mode.

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.