A device, such as an electroabsorption modulator, can modulate a light intensity by controllably absorbing a selectable fraction of the light. The device can include a substrate. A waveguide positioned on the substrate can guide light. An active region positioned on the waveguide can receive guided light from the waveguide, absorb a fraction of the received light, and return a complementary fraction of the received light to the waveguide. Such absorption produces heat, mostly at an input portion of the active region. The input portion of the active region can be thermally coupled to the substrate, which can dissipate heat from the input portion, and can help avoid thermal runaway of the device. The active region can be thermally isolated from the substrate away from the input portion, which can maintain a relatively low thermal mass for the active region, and can increase efficiency when heating the active region.

Embodiments of the invention are directed to a method of fabrication of an electro-optical device. A non-limiting example of the method relies on a waveguide. A trench is opened in the waveguide and a stack of optically active semiconductor materials is directly grown from a bottom wall of the trench and are stacked along a stacking direction that is perpendicular to a main plane of the waveguide. The stack is partly encapsulated in the waveguide, whereby a bottom layer of the stack is in direct contact with a waveguide core material, whereas upper portions of opposite, lateral sides of the stack are exposed. An insulating layer of material is deposited to cover exposed surfaces of the waveguide and structured to form a lateral growth template. Contact layers are laterally grown due to the lateral growth template formed. The contact layers can include an n-doped and p-doped contact layers.

A method is provided for producing, on a wafer-scale, a plurality of optoelectronic chips, including: providing a receiver substrate including a plurality of elementary zones, each being configured to contain one optoelectronic chip, and each including at least one coupling waveguide integrated into the receiver substrate and configured to be optically coupled to a first optoelectronic component; transferring a plurality of pads to the elementary zones such that the pads partially cover the at least one coupling waveguide; and producing the first optoelectronic component from the pads such that each first optoelectronic component is facing the at least one coupling waveguide of a corresponding elementary zone, and, following the transferring step, each pad of the plurality of pads extends over a set of at least two adjacent elementary zones, so as to partially cover the at least one coupling waveguide of each of the adjacent elementary zones.

A phase shift element includes a substrate and a dielectric ridge waveguide (DRW) disposed on the substrate. The DRW includes a dielectric material, and a width of the DRW is less than 500 nanometers (nm). A meta-grating includes a substrate and multiple dielectric ridge wave-guides (DRWs) disposed on the substrate.

Structures and methods for passively aligning a photonic die with a receiving substrate are described. Three alignment surfaces, having dimensions greater than a desired alignment accuracy, may be formed on the photonic die and used to passively and accurately align the photonic die to a receiving substrate in six degrees of freedom. Two of the three alignment surfaces on the photonic die may be formed in a single mask-and-etch process, while the third alignment surface may require no patterning or etching. Three complementary alignment surfaces on the receiving substrate may be formed in a single mask-and-etch process.

An optical element has a substrate; and first to third optical waveguides formed on the substrate and each having a lower clad layer, a core layer, and an upper clad layer, the core layer having a larger refractive index than the lower clad layer and the upper clad layer. The first optical waveguide is optically connected to the second optical waveguide, and the second optical waveguide is optically connected to the third optical waveguide. The first to third optical waveguides have a mesa structure formed in a mesa shape in which at least the upper clad layer and an upper part of the core layer project above the lower clad layer. The core height of the third optical waveguide is lower than the core height of the first optical waveguide. The mesa width of the third optical waveguide is narrower than the mesa width of the first optical waveguide.

A device, such as an electroabsorption modulator, can modulate a light intensity by controllably absorbing a selectable fraction of the light. The device can include a substrate. A waveguide positioned on the substrate can guide light. An active region positioned on the waveguide can receive guided light from the waveguide, absorb a fraction of the received light, and return a complementary fraction of the received light to the waveguide. Such absorption produces heat, mostly at an input portion of the active region. The input portion of the active region can be thermally coupled to the substrate, which can dissipate heat from the input portion, and can help avoid thermal runaway of the device. The active region can be thermally isolated from the substrate away from the input portion, which can maintain a relatively low thermal mass for the active region, and can increase efficiency when heating the active region.

A hybrid grating comprises a first grating layer composed of a first solid-state material, and a second grating layer over the first grating layer and composed of a second solid-state material, the second solid state-material being different than the first solid-state material and having a monocrystalline structure.

According to some implementations, an avalanche photodiode may include a photon absorbing layer to absorb photons of an optical beam and to provide a response. The avalanche photodiode may include a gain response layer to provide a gain to the response. The avalanche photodiode may include a bias control structure connected to the gain response layer to control an electric field in the photon absorbing layer and the gain response layer.

A photonic integrated circuit may include a substrate and an optical waveguide integrated with the substrate. The optical waveguide may include a bend section, wherein a bend shape of the bend section is defined by a curvature function to suppress waveguide mode conversion.