Abstract: A wavelength-tunable laser a circling waveguide having a circling structure; a first coupled waveguide coupled to the circling waveguide in one region; and a second coupled waveguide coupled to the circling waveguide in another region, wherein a first reflection region is connected in the light guiding direction of the first coupled waveguide, an active region and a second reflection region are sequentially connected in the light guiding direction of the second coupled waveguide, and the refractive index of at least part of the circling waveguide is modulated.

Abstract: A semiconductor photonic device includes a first cladding layer formed on a substrate formed with Si, a semiconductor layer formed on the first cladding layer, and a second cladding layer formed on the semiconductor layer. In the semiconductor layer, an active layer, and a p-type layer and an n-type layer disposed in contact with the active layer while sandwiching the active layer in a planar view are formed. A p-type electrode is electrically connected to the p-type layer, and an n-type electrode is electrically connected to the n-type layer. The active layer is formed in a core shape extending in a predetermined direction. This semiconductor photonic device also includes an optical coupling layer that is buried in the first cladding layer in such a manner as to be optically coupled to the active layer, and is formed in a core shape extending along the active layer.

Abstract: An optical semiconductor element includes, in order, a semiconductor laser, an optical waveguide, a loop waveguide, and a ring resonator optically coupled to the loop waveguide, in which a distance between the semiconductor laser and the ring resonator is 1 ?m or more and 200 ?m or less.

Abstract: An embodiment semiconductor optical device includes an optical waveguide including a core, and an active layer extending in the waveguide direction of the optical waveguide for a predetermined distance and arranged in a state in which the active layer can be optically coupled to the core. The core and the active layer are arranged in contact with each other. The core is formed of a material with a refractive index of about 1.5 to 2.2, such as SiN, for example. In addition, the core is formed to a thickness at which a higher-order mode appears. The higher-order mode is an E12 mode, for example.

Abstract: An oscillation unit (101), a measurement unit (102), and a bit generation unit (103) are included. The measurement unit (102) chronologically measures oscillation (for example, thermal oscillation) of a set frequency generated in the oscillation unit (101) at each set time. The bit generation unit (103) generates a bit string by allocating one bit of 0 or 1 to each of sine and cosine components of the oscillation measured by the measurement unit (102).

Abstract: A light receiving device includes, on a substrate, a Si waveguide core provided in a dielectric layer, a first i-type waveguide clad, an i-type core layer, a second i-type waveguide clad, p-type layers disposed on one side of a side surface of a layered structure in a light waveguide direction, the layered structure including the first i-type waveguide clad, the i-type core layer, and the second i-type waveguide clad, n-type layers disposed on the other side, and an electrode on a surface of each of the n-type layers. A width of the Si waveguide core is set to be able to suppress absorption of light in a vicinity of an input edge of the i-type core layer.

Abstract: A semiconductor optical device includes a light emitting layer that emits light in a state of current injection; an optical waveguide in which a width or a thickness in an extending direction (y) of the light emitting layer varies along the extending direction; and a uniform diffraction grating having constant cycle, width and depth, wherein the light emitting layer, the optical waveguide and the uniform diffraction grating are arranged at positions where the light emitting layer, the optical waveguide, and the uniform diffraction grating are optically coupled to one another, the uniform diffraction grating is arranged above the light emitting layer, the optical waveguide is arranged below the light emitting layer, and the optical waveguide includes, in the extending direction, a first portion having a predetermined width, a second portion having a larger width than the width of the first portion, and a third portion having the same width as the width of the first portion.

Abstract: A silicon nitride core is formed on a silicon core via a first silicon oxide layer, and a germanium pattern caused to selectively grow in an opening penetrating through a second silicon oxide layer formed on the silicon nitride core and the first silicon oxide layer is formed on a lower silicon pattern formed to be continuous with the silicon core, thereby constituting a Ge photodiode.

Abstract: Included are an optical waveguide including a first cladding layer formed on a substrate; a core formed on the first cladding layer; and a second cladding layer formed on the first cladding layer so as to cover the core. At least one of the first cladding layer and the second cladding layer is composed of a cladding material of silicon oxide containing deuterium atoms. The number of hydrogen atoms contained in the cladding material is smaller than the number of the deuterium atoms contained in the cladding material.

Abstract: Provided is a tunable laser that prevents basic characteristics of the laser from deteriorating and enables a high-speed control of the oscillation wavelength. The tunable laser includes a semiconductor gain portion including a III-V compound semiconductor, an optical feedback portion configured to diffract light generated in the semiconductor gain portion and feed the diffracted light back to the semiconductor gain portion, and an optical modulation portion including an optical waveguide that contains doped indirect transition-type silicon. The semiconductor gain portion and the optical modulation portion are disposed so that optical modes thereof overlap each other, and the semiconductor gain portion includes an embedded active layer thin film of a type in which a current is injected in a lateral direction.

Abstract: An embodiment semiconductor optical device includes an optical waveguide including a core, and an active layer extending in the waveguide direction of the optical waveguide for a predetermined distance and arranged in a state in which the active layer can be optically coupled to the core. The core and the active layer are arranged in contact with each other. The core is formed of a material with a refractive index of about 1.5 to 2.2, such as SiN, for example. In addition, the core is formed to a thickness at which a higher-order mode appears. The higher-order mode is an E12 mode, for example.

Abstract: Included are an optical waveguide including a first cladding layer formed on a substrate; a core formed on the first cladding layer; and a second cladding layer formed on the first cladding layer so as to cover the core. At least one of the first cladding layer and the second cladding layer is composed of a cladding material of silicon oxide containing deuterium atoms. The number of hydrogen atoms contained in the cladding material is smaller than the number of the deuterium atoms contained in the cladding material.

Abstract: A wavelength tunable laser formed on a substrate made of single-crystal silicon is provided. The wavelength tunable laser includes a light emitting portion made of a III-V compound semiconductor, and external resonators provided with an optical filter. Cores included in the external resonators are made of one of SiN, SiON, and SiOn (n is smaller than 2).