Abstract: An optical modulator includes a Mach-Zehnder interferometer including (i) a first optical waveguide including a first semiconductor junction diode, and (ii) a second optical waveguide including a second semiconductor junction diode. A semiconductor region connects the first and second semiconductor junction diodes such that a distance between the first and second optical waveguides is less than 2.0 ?m for at least a portion of a longitudinal direction of the optical modulator. In another aspect, a method of modulating an optical signal includes splitting input light into first and second optical transmission paths; modulating a phase difference between light in the first optical transmission path and light in the second optical transmission path without applying a bias voltage through an impedance less than 100 ohm between the first and second optical transmission paths; and combining light that is output from the first and second optical transmission paths.

Abstract: An optical multiple-input-multiple-output (MIMO) receiver includes an input port configured to receive input light; a Stokes measurement apparatus configured to generate measurements of Stokes parameters; an optical MIMO demultiplexer configured to generate a plurality of demultiplexed output light signals based on (i) the input light and (ii) the measurements of the Stokes parameters generated by the Stokes measurement apparatus; and a plurality of output ports configured to output the plurality of demultiplexed output light signals generated by the optical MIMO demultiplexer. In particular, the Stokes measurement apparatus is connected to the optical MIMO demultiplexer in a parallel arrangement.

Abstract: Implementations are directed to configurable intensity-modulation direct-detection (IM-DD) optical transceivers that are configurable between single-polarization (SP) operation and dual-polarization (DP) operation.

Abstract: A multi-wavelength dual-polarization (DP) receiver includes an input port configured to receive input light; an optical polarization splitter and rotator configured to split the input light into a first optical waveguide and a second optical waveguide; a first wavelength demultiplexer connected to the first optical waveguide and configured to output wavelength-demultiplexed light into a first plurality of optical waveguides; a second wavelength demultiplexer connected to the second optical waveguide and configured to output wavelength-demultiplexed light into a second plurality of optical waveguides; and a plurality of optical multi-input-multi-output (MIMO) polarization demultiplexers, each of which is connected to a respective one of the first plurality of optical waveguides and one of the second plurality of optical waveguides.

Abstract: A silicon-photonic optical modulator includes at least one optical input and at least one optical waveguide that is connected to the at least one optical input. The at least one optical waveguide is configured to propagate quasi-transverse-magnetic (quasi-TM) polarized light, where each of the at least one optical waveguide is configured as a rib waveguide that includes a rib arranged on a slab. The silicon-photonic optical modulator also includes at least one electrode configured to apply at least one electric field to the quasi-TM polarized light in the at least one optical waveguide. In some implementations, a height of the rib waveguide is greater than 0.85 ?/n, where A is a free-space wavelength of light and n is a refractive index of silicon in the silicon-photonic optical modulator, and a width of the rib waveguide is greater than a thickness of the slab.

Abstract: An optical modulator includes a Mach-Zehnder interferometer including (i) a first optical waveguide including a first semiconductor junction diode, and (ii) a second optical waveguide including a second semiconductor junction diode. A semiconductor region connects the first and second semiconductor junction diodes such that a distance between the first and second optical waveguides is less than 2.0 µm for at least a portion of a longitudinal direction of the optical modulator. In another aspect, a method of modulating an optical signal includes splitting input light into first and second optical transmission paths; modulating a phase difference between light in the first optical transmission path and light in the second optical transmission path without applying a bias voltage through an impedance less than 100 ohm between the first and second optical transmission paths; and combining light that is output from the first and second optical transmission paths.

Abstract: A 2×2 optical multi-input-multi-output (MIMO) demultiplexer is disclosed. A first optical phase shifter applies a first relative phase shift between a first pair of optical transmission paths that are received from MIMO inputs, and a first 2×2 optical coupler combines the first pair of optical transmission paths and outputs a second pair of optical transmission paths. A second optical phase shifter applies a second relative phase shift between the second pair of optical transmission paths, and a second 2×2 optical coupler combines the second pair of optical transmission paths and outputs a third pair of optical transmission paths. A third optical phase shifter applies a third relative phase shift between the third pair of optical transmission paths, and a third 2×2 optical coupler combines the third pair of optical transmission paths and outputs a fourth pair of optical transmission paths, which are output by a pair of MIMO outputs.

Abstract: An optical modulator includes a Mach-Zehnder interferometer including (i) a first optical waveguide including a first semiconductor junction diode, and (ii) a second optical waveguide including a second semiconductor junction diode. A semiconductor region connects the first and second semiconductor junction diodes such that a distance between the first and second optical waveguides is less than 2.0 ?m for at least a portion of a longitudinal direction of the optical modulator. In another aspect, a method of modulating an optical signal includes splitting input light into first and second optical transmission paths; modulating a phase difference between light in the first optical transmission path and light in the second optical transmission path without applying a bias voltage through an impedance less than 100 ohm between the first and second optical transmission paths; and combining light that is output from the first and second optical transmission paths.

Abstract: An optical modulator includes a Mach-Zehnder interferometer including (i) a first optical waveguide including a first semiconductor junction diode, and (ii) a second optical waveguide including a second semiconductor junction diode. A semiconductor region connects the first and second semiconductor junction diodes such that a distance between the first and second optical waveguides is less than 2.0 ?m for at least a portion of a longitudinal direction of the optical modulator. In another aspect, a method of modulating an optical signal includes splitting input light into first and second optical transmission paths; modulating a phase difference between light in the first optical transmission path and light in the second optical transmission path without applying a bias voltage through an impedance less than 100 ohm between the first and second optical transmission paths; and combining light that is output from the first and second optical transmission paths.

Abstract: A method, comprising modulating digital data onto an optical carrier. Modulating includes intensity splitting the optical carrier in an input optical coupler of an interferometer. The interferometer including two or more controllable optical waveguides located on a substrate, each controllable optical waveguide connecting the input optical coupler to an output optical coupler of the interferometer and having a two-state modulator along a segment thereof. Modulating include optically modulating separate data streams onto each of the optical carriers produced by the splitting. The two or more controllable optical waveguides are connected to transmit an output to the output optical coupler, substantially different light amplitudes and/or phases when the two-state modulators of the two or more controllable optical waveguides are in different states, as driven by the data streams having different information content.

Abstract: Undirected cross connects are provided based on wavelength-selective switches. An undirected Cantor network is disclosed where the switch nodes are wavelength selective switches. An undirected Clos cross connect is also disclosed where one or more undirected switches are undirected Cantor networks having at least one wavelength selective switch.

Abstract: An optical device comprising a tunable optical frequency comb generator. The comb generator includes an interferometer, and an optical feed-back loop waveguide.

Abstract: A method, comprising modulating digital data onto an optical carrier. Modulating includes intensity splitting the optical carrier in an input optical coupler of an interferometer. The interferometer including two or more controllable optical waveguides located on a substrate, each controllable optical waveguide connecting the input optical coupler to an output optical coupler of the interferometer and having a two-state modulator along a segment thereof. Modulating include optically modulating separate data streams onto each of the optical carriers produced by the splitting. The two or more controllable optical waveguides are connected to transmit an output to the output optical coupler, substantially different light amplitudes and/or phases when the two-state modulators of the two or more controllable optical waveguides are in different states, as driven by the data streams having different information content.

Abstract: An optical device comprising a tunable optical frequency comb generator. The comb generator includes an interferometer, and an optical feed-back loop waveguide.

Abstract: An optical modulator device comprising an interferometer. The interferometer includes an input optical coupler, an output optical coupler, and two or more controllable optical waveguides located on a substrate. Each controllable optical waveguide connects the input optical coupler to the output optical coupler and has two-state modulator along a segment thereof. The two or more controllable optical waveguides are connected to transmit an output to the output optical coupler, substantially different light amplitudes and/or phases when the two-state modulators of the two controllable optical waveguides are in different states, as driven by data streams having different information content. The two or more controllable optical waveguides are configured to modulate the light amplitudes and/or phases in a substantially same manner when the two-state modulators are in identical states.

Abstract: Various exemplary embodiments relate to an optical isolator in an integrated optical circuit including: a first optical modulator configured to provide a first periodic phase modulation on an input optical signal; a second optical modulator configured to provide a second periodic phase modulation on the modulated optical signal; and an optical waveguide having a length L connecting the first optical modulator to the second optical modulator; wherein the phase difference between the first and second periodic phase modulation is ?/2, and wherein the length L of the optical waveguide causes a phase delay of ?/2 on an optical signal traversing the optical waveguide.

Abstract: An optical device comprising a tunable optical frequency comb generator. The comb generator includes an interferometer, and an optical feed-back loop waveguide.

Abstract: A photonic integrated circuit (PIC) having a waveguide-grating coupler with two evanescently coupled waveguides. The first waveguide is fabricated using materials suitable for manufacturing active optical elements in the PIC. The second waveguide is fabricated using materials capable of providing a relatively high index-of-refraction contrast for the constituent waveguide grating. The waveguide-grating coupler is compatible with the III-V semiconductor technology while being relatively easy to fabricate on an industrial scale.

Abstract: An optical device comprising a substrate having a planar surface and having an optical core thereon. The device also comprises a two-dimensional grating located in the optical core, said two-dimensional grating being formed by a regular two-dimensional pattern of light-refractive structures, one of said light-refractive structures being located at each node of a regular 2D lattice located in a laterally bounded region. The device also comprises first and second optical waveguides being on the planar substrate and having ends end-coupled to the two-dimensional grating, the first optical waveguide being such that a direction of propagation near the end thereof is substantially along a primitive lattice vector of said 2D lattice, the second optical waveguide being such that a direction of propagation near the end thereof is not-parallel to a primitive lattice vector of said regular 2D lattice.

Abstract: An optical device comprising a planar waveguide located on a planar substrate, the planar waveguide including a light-transmissive layer and an optical grating coupler being located along the planar substrate and being adjacent to and optically coupled to the planar waveguide. The optical coupler includes an optical grating of the light-transmissive layer. The optical grating includes a periodic arrangement of light-refractive structures and one or more slotted openings separating the optical grating into two or more grating segments that have long axes that are substantially parallel to a propagation direction of a light beam configured to pass between the planar waveguide and the optical coupler. Pitch distances between adjacent ones of the grating segments are less than a wavelength of the light beam divided by an effective refractive index of the light-transmissive layer.