Abstract: An athermal ring optical modulator includes a first clad layer, a ring optical resonator, a second clad layer, an input-output optical waveguide, a first conduction type region, and a second conduction type region. The ring optical resonator has a rib optical waveguide with a convex portion formed on a semiconductor slab layer. The semiconductor slab layer is formed on the first clad layer. The second clad layer covers an upper side of the rib optical waveguide. The input-output optical waveguide couples optically with the ring optical resonator. The first and second conduction type regions are formed in the semiconductor slab layer inside and outside the ring optical resonator, respectively. In addition, the second clad layer includes a material having a negative thermo-optical coefficient. The semiconductor slab layer outside the convex portion is thinner than the semiconductor slab layer inside the convex portion.

Abstract: A photoelectric conversion element of an embodiment is a photoelectric conversion element which performs photoelectric conversion by receiving illumination light having n light emission peaks having a peak energy Ap (eV) (where 1?p?n and 2?n) of 1.59?Ap?3.26 and a full width at half maximum Fp (eV) (where 1?p?n and 2?n), wherein the photoelectric conversion element includes m photoelectric conversion layers having a band gap energy Bq (eV) (where 1?q?m and 2?m?n), and the m photoelectric conversion layers each satisfy the relationship of Ap?Fp<Bq?Ap with respect to any one of the n light emission peaks.

Abstract: An optical interconnection device includes a light-emitting element, a light-receiving element, and an optical waveguide. Both the light-emitting element and the light-receiving element have a layered structure and are formed on a silicon substrate. At least a portion of the light-emitting element is embedded in an insulator. At least a portion of the light-receiving element is embedded in the insulator. The optical waveguide is formed over the insulator, and is optically coupled to the light-emitting element and the light-receiving element by distributed coupling.

Abstract: In one embodiment, a semiconductor laser includes a semiconductor laminated body formed in a ring shape and first and second electrodes. The semiconductor laminated body includes an active layer, first and second cladding layers formed on both sides of the active layer, first and second contact layers formed on the first and second cladding layers, and first and second modified layers. The first and second modified layers are formed by selectively modifying the inner peripheral sidewalls and the outer peripheral sidewalls of the first and second cladding layers so as to have a refractive index lower than the refractive indexes of the first and second cladding layers. The first and second contact layers are electrically connected to the first and second electrodes.

Abstract: An optical transmission-reception system includes: a light-emitting element having a first semiconductor multilayer structure with a ring- or disk-like shape and generating a first optical signal and a second optical signal rotating in a direction opposite to the first optical signal; a first optical waveguide optically coupled with the light-emitting element and propagating the first optical signal; a second optical waveguide optically coupled with the light-emitting element and propagating the second optical signal; and a light-receiving element having a second semiconductor multilayer structure with a ring- or disk-like shape, optically coupled with the first and second optical waveguides, and optically receiving the first and second optical signals.

Abstract: An athermal ring optical modulator includes a first clad layer, a ring optical resonator, a second clad layer, an input-output optical waveguide, a first conduction type region, and a second conduction type region. The ring optical resonator has a rib optical waveguide with a convex portion formed on a semiconductor slab layer. The semiconductor slab layer is formed on the first clad layer. The second clad layer covers an upper side of the rib optical waveguide. The input-output optical waveguide couples optically with the ring optical resonator. The first and second conduction type regions are formed in the semiconductor slab layer inside and outside the ring optical resonator, respectively. In addition, the second clad layer includes a material having a negative thermo-optical coefficient. The semiconductor slab layer outside the convex portion is thinner than the semiconductor slab layer inside the convex portion.

Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer and a laser resonator. The first semiconductor layer includes a first portion and a second portion juxtaposed with the first portion. The laser resonator is provided on the first portion and has a ring-shaped resonator structure circled along a major surface of the first semiconductor layer. The second portion guides light emitted from the laser resonator.

Abstract: In one embodiment, a semiconductor laser includes a semiconductor laminated body formed in a ring shape and first and second electrodes. The semiconductor laminated body includes an active layer, first and second cladding layers formed on both sides of the active layer, first and second contact layers formed on the first and second cladding layers, and first and second modified layers. The first and second modified layers are formed by selectively modifying the inner peripheral sidewalls and the outer peripheral sidewalls of the first and second cladding layers so as to have a refractive index lower than the refractive indexes of the first and second cladding layers. The first and second contact layers are electrically connected to the first and second electrodes.

Abstract: An optical modulation device of an embodiment includes: a first p-type semiconductor region; a first n-type semiconductor region; a first low-impurity-density semiconductor region formed between the first p-type semiconductor region and the first n-type semiconductor region; a second n-type semiconductor region formed on an outer side of the first p-type semiconductor region via a second low-impurity-density semiconductor region; and a second p-type semiconductor region formed on an outer side of the first n-type semiconductor region via a third low-impurity-density semiconductor region. The carrier density in the first low-impurity-density semiconductor region is changed by current injection. The phase of light propagated through an optical waveguide structure that includes at least part of the first low-impurity-density semiconductor region is modulated.

Abstract: An optical waveguide circuit includes: a lower cladding layer formed on a substrate; a first optical waveguide formed on the lower cladding layer so as to partition the lower cladding layer into a first portion and a second portion; a second optical waveguide formed on the first portion, the second optical waveguide including a tip end portion directed toward a side face of the first optical waveguide, the tip end portion being narrowed in a tapered manner; and a third optical waveguide formed on the second portion, the third optical waveguide including a tip end portion directed toward the tip end portion of the second optical waveguide, a tip end portion of the third optical waveguide being narrowed in a tapered manner.

Abstract: It makes possible to inject a current into the current confinement region substantially uniformly. A surface emitting type optical semiconductor device includes a semiconductor active layer provided above a substrate; a first and second reflecting mirror layers sandwiching the semiconductor active layer to form an optical cavity in a direction perpendicular to the substrate; a plurality of current confinement regions provided in the second reflecting mirror layer so as to be separated by an impurity region having impurities; a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions; and an electrode portion which injects a current into the semiconductor active layer. The electrode portion comprising a first electrode provided on the semiconductor current diffusion layer so as to surround the current confinement regions and a second electrode provided on an opposite side of the substrate from the semiconductor active layer.

Abstract: An optical waveguide circuit includes: a lower cladding layer formed on a substrate; a first optical waveguide formed on the lower cladding layer so as to partition the lower cladding layer into a first portion and a second portion; a second optical waveguide formed on the first portion, the second optical waveguide including a tip end portion directed toward a side face of the first optical waveguide, the tip end portion being narrowed in a tapered manner; and a third optical waveguide formed on the second portion, the third optical waveguide including a tip end portion directed toward the tip end portion of the second optical waveguide, a tip end portion of the third optical waveguide being narrowed in a tapered manner.

Abstract: It makes possible to inject a current into the current confinement region substantially uniformly. A surface emitting type optical semiconductor device includes a semiconductor active layer provided above a substrate; a first and second reflecting mirror layers sandwiching the semiconductor active layer to form an optical cavity in a direction perpendicular to the substrate; a plurality of current confinement regions provided in the second reflecting mirror layer so as to be separated by an impurity region having impurities; a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions; and an electrode portion which injects a current into the semiconductor active layer. The electrode portion comprising a first electrode provided on the semiconductor current diffusion layer so as to surround the current confinement regions and a second electrode provided on an opposite side of the substrate from the semiconductor active layer.

Abstract: It makes possible to inject a current into the current confinement region substantially uniformly. A surface emitting type optical semiconductor device includes a semiconductor active layer provided above a substrate; a first and second reflecting mirror layers sandwiching the semiconductor active layer to form an optical cavity in a direction perpendicular to the substrate; a plurality of current confinement regions provided in the second reflecting mirror layer so as to be separated by an impurity region having impurities; a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions; and an electrode portion which injects a current into the semiconductor active layer. The electrode portion comprising a first electrode provided on the semiconductor current diffusion layer so as to surround the current confinement regions and a second electrode provided on an opposite side of the substrate from the semiconductor active layer.

Abstract: In a vertical cavity surface emitting laser diode manufactured on a non-off-angle substrate with a (100)-oriented plane or the like, anisotropic stress is applied to a central portion of an active layer by forming a asymmetrical oxidation structure in an Al high concentration portion in the mesa, so that polarization controllability of a device can be improved.

Abstract: It makes possible to inject a current into the current confinement region substantially uniformly. A surface emitting type optical semiconductor device includes a semiconductor active layer provided above a substrate; a first and second reflecting mirror layers sandwiching the semiconductor active layer to form an optical cavity in a direction perpendicular to the substrate; a plurality of current confinement regions provided in the second reflecting mirror layer so as to be separated by an impurity region having impurities; a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions; and an electrode portion which injects a current into the semiconductor active layer. The electrode portion comprising a first electrode provided on the semiconductor current diffusion layer so as to surround the current confinement regions and a second electrode provided on an opposite side of the substrate from the semiconductor active layer.

Abstract: It is made possible to obtain high performance having high controllability in polarization mode even when a vertical cavity surface emitting laser diode is fabricated on an ordinary substrate with a plane orientation (100) plane or the like. A vertical cavity surface emitting laser diode includes: a substrate; a semiconductor active layer which is formed on the substrate and has a light emitting region; a first reflecting mirror and a second reflecting mirror sandwiching the semiconductor active layer; a first recess which has a first groove depth penetrating at least the semiconductor active layer from the outermost layer of the first reflecting mirror; a second recess having a second groove depth shallower than the first groove depth; a mesa portion which is surrounded by the first and second recesses; and an insulating film which is buried in the first recess.

Abstract: A vertical-cavity surface emitting laser diode comprises: a first and a second reflectors; an active layer provided between the first and the second reflectors; and an oxidizee layer having a non-oxidized part and an oxidized part provided around the non-oxidized part. An electric current is injected into the non-oxidized part. The oxidizee layer has a proton-containing part including proton at least at a position substantially enclosing the non-oxidized part.

Abstract: In a vertical cavity surface emitting laser diode manufactured on a non-off-angle substrate with a (100)-oriented plane or the like, anisotropic stress is applied to a central portion of an active layer by forming a asymmetrical oxidation structure in an Al high concentration portion in the mesa, so that polarization controllability of a device can be improved.

Abstract: A vertical-cavity surface emitting laser diode comprises: a first and a second reflectors; an active layer provided between the first and the second reflectors; and an oxidizee layer having a non-oxidized part and an oxidized part provided around the non-oxidized part. An electric current is injected into the non-oxidized part. The oxidizee layer has a proton-containing part including proton at least at a position substantially enclosing the non-oxidized part.