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 beam steering apparatus includes a substrate; at least one light source provided on the substrate; a first waveguide configured to transmit a first light beam radiated from the at least one light source; at least one beam splitter configured to split the first light beam transmitted by the first waveguide to obtain a second light beam; a second waveguide configured to receive the second light beam; and a quantum dot optical amplifier provided on the second waveguide and comprising a barrier layer, a quantum dot layer, and a wetting layer, the quantum dot optical amplifier being configured to modulate a phase of the second light beam, and to amplify an intensity of the second light beam.

Photonic devices having a photonic waveguiding layer, and a cladding layer, disposed on the photonic waveguiding layer, and where the cladding section is a material comprising Scandium. The cladding layer may include a material comprising Al.sub.1-xSc.sub.xN material where 0<x≤0.45.

Photonic devices having a quantum well structure that includes a Group III-N material, and a Al.sub.1-xSc.sub.xN cladding layer disposed on the quantum well structure, where 0<x≤0.45, the Al.sub.1-xSc.sub.xN cladding layer having a lower refractive index than the index of refraction of the quantum well structure.

An optical integrated element includes: a substrate; a first waveguide region in which a lower cladding layer, a first core layer, and an upper cladding layer are sequentially laminated in this order on the substrate; and an active region in which the lower cladding layer, a second core layer, a quantum well layer that amplifies light when a current is injected, and the upper cladding layer are sequentially laminated on the substrate. Further, the second core layer and the quantum well layer are close to each other within a range of a mode field of light guided in the second core layer, and the first core layer is butt-jointed to the second core layer and the quantum well layer.

An optoelectronic device. The device comprising: a multi-layered optically active stack, including one or more layers comprising a lll-V semiconductor material; an input waveguide, arranged to guide light into the stack; and an output waveguide, arranged to guide light out of the stack. The multi-layered optically active stack is butt or edge coupled to the input waveguide and output waveguide.

A photonic chip. In some embodiments, the photonic chip includes a waveguide; and an optically active device comprising a portion of the waveguide. The waveguide may have a first end at a first edge of the photonic chip; and a second end, and the waveguide may have, everywhere between the first end and the second end, a rate of change of curvature having a magnitude not exceeding 2,000/mm.sup.2.

The present invention provides a highly reliable, high-speed, and low-loss semiconductor optical modulation element that protects a pin junction structure in a modulation region against reverse voltage ESD by configuring an additional capacity having a thyristor structure between a plurality of feeding pad electrodes. An n-type contact layer, an n-type cladding layer, a non-doped core/cladding layer, a p-type cladding layer, and a p-type contact layer are sequentially laminated on the substrate surface. A Mach-Zehnder interferometric waveguide and a plurality of feeding pad installation sections are formed by dry etching. The n-type contact layer and the n-type cladding layer are removed except for a modulation region of the Mach-Zehnder interferometric waveguide and a feeding region in which the feeding pad installation sections are formed so that the modulation region and the semiconductor of the lower part of the feeding region are electrically isolated from each other. The feeding pads are formed on the common n-type contact layer and n-type cladding layer. A thyristor structure of a pinip junction is formed between the feeding pads.

The present invention provides a highly reliable, high-speed, and low-loss semiconductor optical modulation element that protects a pin junction structure in a modulation region against reverse voltage ESD by configuring an additional capacity having a thyristor structure between a plurality of feeding pad electrodes. An n-type contact layer, an n-type cladding layer, a non-doped core/cladding layer, a p-type cladding layer, and a p-type contact layer are sequentially laminated on the substrate surface. A Mach-Zehnder interferometric waveguide and a plurality of feeding pad installation sections are formed by dry etching. The n-type contact layer and the n-type cladding layer are removed except for a modulation region of the Mach-Zehnder interferometric waveguide and a feeding region in which the feeding pad installation sections are formed so that the modulation region and the semiconductor of the lower part of the feeding region are electrically isolated from each other. The feeding pads are formed on the common n-type contact layer and n-type cladding layer. A thyristor structure of a pinip junction is formed between the feeding pads.

An electro-optically active device comprising: a silicon on insulator (SOI) substrate including a silicon base layer, a buried oxide (BOX) layer on top of the silicon base layer, a silicon on insulator (SOI) layer on top of the BOX layer, and a substrate cavity which extends through the SOI layer, the BOX layer and into the silicon base layer, such that a base of the substrate cavity is formed by a portion of the silicon base layer; an electro-optically active waveguide including an electro-optically active stack within the substrate cavity; and a buffer region within the substrate cavity beneath the electro-optically active waveguide, the buffer region comprising a layer of Ge and a layer of GaAs.