Structures for a polarization switch and methods of fabricating a structure for a polarization switch. A waveguide core is located on a substrate. The waveguide core is composed of silicon nitride. An active layer is positioned proximate to a section of the waveguide core. The active layer composed of a phase change material having a first state with a first refractive index and a second state with a second refractive index.

An optical device includes a first substrate, a second substrate, a plurality of separation walls, one or more optical waveguides, and one or more spacers. The first substrate has a surface which extends in a first direction and a second direction intersecting the first direction. The second substrate faces the first substrate. The plurality of separation walls are positioned between the first substrate and the second substrate and extend in the first direction. The one or more optical waveguides are positioned between the first substrate and the second substrate and include one or more dielectric members which are positioned between the plurality of separation walls and which extend in the first direction. The one or more spacers are directly or indirectly sandwiched between the first substrate and the second substrate and positioned around the one or more optical waveguides.

A method of manufacturing an electro-optically active device. The method comprising the steps of: etching a cavity on a silicon-on-insulator wafer; providing a sacrificial layer adjacent to a substrate of a lll-V semiconductor wafer; epitaxially growing an electro-optically active structure on the lll-V semiconductor wafer; etching the epitaxially grown optically active structure into an electro-optically active mesa; disposing the electro-optically active mesa in the cavity of the silicon-on-insulator wafer and bonding a surface of the electro-optically active mesa, which is distal to the sacrificial layer, to a bed of the cavity; and removing the sacrificial layer between the substrate of the lll-V semiconductor wafer and the electro-optically active mesa.

Structures for an electro-optic modulator and methods of fabricating a structure for an electro-optic modulator. The electro-optic modulator has a layer stack arranged over a section of a waveguide core. The layer stack includes a first layer, a second layer, and a third layer. The first layer, the second layer, and the third layer are each composed of either copper or indium-tin oxide.

Embodiments include apparatuses, methods, and systems including a semiconductor photonic device having a substrate, a waveguide disposed above the substrate, a phase change layer disposed above the waveguide, and a heater disposed above the phase change layer. The waveguide has a modifiable refractive index based at least in part on a state of a phase change material included in the phase change layer. The phase change material of the phase change layer is in a first state of a set of states, and the waveguide has a first refractive index determined based on the first state of the phase change material. The heater is to generate heat to transform the phase change material to a second state of the set of states, and the waveguide has a second refractive index determined based on the second state of the phase change material. Other embodiments may also be described and claimed.

Structures for an electro-optic modulator and methods of fabricating a structure for an electro-optic modulator. An electro-optic modulator is positioned proximate to a section of a waveguide core. The electro-optic modulator includes an active layer and a confinement layer. The active layer is composed of a first material, the confinement layer is composed of a second material with a different composition than the first material, the first material has a refractive index that is variable under an applied bias voltage, and the second material has a permittivity with an imaginary part that ranges from 0 to about 15.

Structures for an electro-optic modulator and methods of fabricating a structure for an electro-optic modulator. An electro-optic modulator is arranged over a portion of a waveguide core. The electro-optic modulator includes an electrode, an active layer arranged adjacent to the electrode, and a dielectric layer including a portion that has a lateral arrangement between the electrode and the active layer. The active layer is composed of a material having a refractive index that is a function of a bias voltage applied to the electrode and the active layer.

An on-chip optical phased array includes an array of photonic antenna units connected in series by photonic waveguides and arranged in a two-dimensional array to produce complex still and scanning optical patterns through optical interference effect. Each antenna unit includes an output photonic antenna (e.g. grating antenna), and a waveguide phase shifter for adjusting the optical phase of the optical beam output by the antenna unit. The grating antenna and the waveguide phase shifter are formed in the same optical wave guiding layer which includes a core layer between two cladding layers. The grating antennas may be a shallow-etched structure or a deep-etched edge-modulated grating. The optical phased array, including the array of photonic antenna units and the electrodes that connect and provide electrical power to them, can be made on a single chip of silicon using complementary metal-oxide-semiconductor (CMOS) or compatible fabrication processes.

Embodiments include apparatuses, methods, and systems including a semiconductor photonic device having a substrate, a waveguide disposed above the substrate, a phase change layer disposed above the waveguide, and a heater disposed above the phase change layer. The waveguide has a modifiable refractive index based at least in part on a state of a phase change material included in the phase change layer. The phase change material of the phase change layer is in a first state of a set of states, and the waveguide has a first refractive index determined based on the first state of the phase change material. The heater is to generate heat to transform the phase change material to a second state of the set of states, and the waveguide has a second refractive index determined based on the second state of the phase change material. Other embodiments may also be described and claimed.

An optical waveguide circuit includes a polarization beam splitter connecting to a first input optical waveguide; an optical interference element receiving one of orthogonally polarization-split lights of a first light from the polarization beam splitter, and one of orthogonally-polarized lights from a second light input to a second input optical waveguide, the optical interference element causing interference therebetween; a first connection optical waveguide connecting the polarization beam splitter and the optical interference element; and a second connection optical waveguide connecting the second input optical waveguide and the optical interference element. The first and the second input optical waveguides have a straight-line shape or an S-shape including a first bending portion and a second bending portion to cancel the polarization-rotation of light taking place in the first bending portion. The polarization beam splitter, the first and the second connection optical waveguides, and the optical interference element are arranged in an S-shape.