Abstract: An optical modulator includes an optical waveguide, first and second electrodes, and a first wiring electrode. The first electrode is on one side of the optical waveguide in a height direction of the optical modulator and extends along a portion of the optical waveguide. The second electrode is on another side of the optical waveguide in the height direction of the optical modulator. The first wiring electrode is on a side of the first electrode opposite to the optical waveguide in the height direction and is electrically connected to the first electrode. The first wiring electrode includes a wiring portion extending from an end portion in an extension direction of the first electrode when viewed along the height direction.

Abstract: An optical modulator includes an optical waveguide and first and second electrodes. The first electrode is located on one side in a height direction of the optical modulator with respect to the optical waveguide. The first electrode includes one end portion and another end portion overlapping with the optical waveguide in a view along the height direction. The second electrode is located on the other side in the height direction with respect to the optical waveguide and applies an electric field to the optical waveguide together with the first electrode. In the view along the height direction, a length of the first electrode is different from a length of the optical waveguide from a position of the one end portion to a position of the another end portion of the first electrode.

Abstract: An ultrasonic transducer includes first and second acoustic transducers and a housing with a bottomed tubular shape. The second acoustic transducer includes an annular section supporting a second membrane section and contacting an entire periphery of the second membrane section, and an acoustic matching plate facing the second membrane section and spaced apart from the second membrane section. The acoustic matching plate is connected to a surrounding wall portion defining a sealed space with the housing. An ultrasonic transmission path sandwiched between the first membrane section and the second membrane section is provided in the sealed space. A maximum inner width of the ultrasonic transmission path is smaller than a maximum inner width of the surrounding wall portion.

Abstract: An optical modulator includes an optical waveguide, a first electrode, a second electrode, and a first low dielectric constant layer. The optical waveguide includes a material having an electro-optic effect. The first electrode includes a semiconductor material and is spaced by a gap from the optical waveguide. The second electrode is positioned to provide a potential difference with the first electrode and apply an electric field to the optical waveguide. The first low dielectric constant layer has a refractive index smaller than that of the optical waveguide, and is provided in the gap between the first electrode and the optical waveguide.

Abstract: An optical modulator includes an optical waveguide including a material having an electro-optic effect, a first electrode, and a second electrode. The first electrode includes a semiconductor material. The second electrode includes a metal material and is positioned to provide a potential difference with respect to the first electrode to apply an electric field to the optical waveguide.

Abstract: An optical modulator includes an optical waveguide, a first electrode, two second electrodes, and a third electrode that generates a potential difference from the first electrode and the second electrodes. Each second electrode receives a voltage with an identical phase to a voltage applied to the first electrode. In a cross-sectional view perpendicular to a direction in which the optical waveguide extends, the first electrode is on a first side of the optical waveguide in a thickness direction, one second electrode is spaced apart from the first electrode on a first side of the first electrode in a width direction of the optical waveguide, the other second electrode is spaced apart from the first electrode on a second side of the first electrode in the width direction of the optical waveguide, and the third electrode is on a second side of the optical waveguide in the thickness direction.

Abstract: An optical modulator includes an optical waveguide, a first electrode, a second electrode, and a low dielectric constant layer. The optical waveguide is made of a material having an electro-optic effect. The first and second electrodes generate a potential difference with each other. In a cross-sectional view in a direction perpendicular or substantially perpendicular to an extending direction of the optical waveguide, the first electrode is on first side of the optical waveguide in a width direction and on first side of the optical waveguide in a thickness direction, the second electrode is on the second side of the optical waveguide in the width direction and on the second side of the optical waveguide in the thickness direction, the low dielectric constant layer is interposed between the first electrode and the optical waveguide, and a portion of the first electrode adjacent to the optical waveguide is in the low dielectric constant layer.

Abstract: A MEMS device includes a first substrate with a MEMS structure, a second substrate facing the first substrate with an interval therebetween, a first joint portion that includes a eutectic layer including a eutectic alloy of different metals between the first and second substrates and that surrounds the MEMS structure and is joined to the first and second substrates, a conductive contact layer between the first and second substrates and that is in contact with the first and second substrates and does not melt at a temperature at which the plural types of metal undergo a metal eutectic reaction, and an insulating layer located on the contact layer and electrically insulated.

Abstract: A MEMS device includes a first substrate having a MEMS structure, a second substrate opposing the first substrate with an interval therebetween in an opposing direction, a first joint portion that includes a eutectic layer including as a main material, a eutectic alloy of plural types of metal, that is provided between the first and second substrates and surrounds the MEMS structure as viewed in the opposing direction, and that is joined to the first and second substrates, and a contact layer that is provided between the first and second substrates and is in contact with the first and second substrates. The contact layer includes a portion of the plural types of metal included in the first joint portion.

Abstract: An ultrasonic transducer includes first and second acoustic transducers and a housing with a bottomed tubular shape. The second acoustic transducer includes an annular section supporting a second membrane section and contacting an entire periphery of the second membrane section, and an acoustic matching plate facing the second membrane section and spaced apart from the second membrane section. The acoustic matching plate is connected to a surrounding wall portion defining a sealed space with the housing. An ultrasonic transmission path sandwiched between the first membrane section and the second membrane section is provided in the sealed space. A maximum inner width of the ultrasonic transmission path is smaller than a maximum inner width of the surrounding wall portion.

Abstract: A piezoelectric element that includes a substrate, a lower electrode layer on the substrate, an intermediate layer on the lower electrode layer, and an upper electrode layer on the intermediate layer. The intermediate layer includes a first piezoelectric layer including an aluminum nitride as a main component thereof and located between the lower electrode layer and the upper electrode layer, a first buffer layer including an aluminum nitride as a main component and located between the first piezoelectric layer and the upper electrode layer, a first intermediate electrode layer located between the first buffer layer and the upper electrode layer, and a second piezoelectric layer located between the first intermediate electrode layer and the upper electrode layer.

Abstract: A gallium nitride structure that includes: a substrate; a gallium nitride layer opposed to the substrate and containing gallium nitride as a main component thereof; and a first electrode between the gallium nitride layer and the substrate. The first electrode includes at least one hafnium layer containing a single metal of hafnium as a main component thereof, and the at least one hafnium layer is in contact with the gallium nitride layer.

Abstract: A method of manufacturing a dielectric device includes epitaxially growing a metal film on a substrate, forming a dielectric film on the metal film such that the dielectric film has a preferentially oriented structure, forming a first electrode film having a non-oriented or amorphous structure on the dielectric film, removing the substrate and the metal film from the dielectric film or removing the substrate from the metal film, and forming a second electrode film having a non-oriented or amorphous structure on the dielectric film or the metal film.

Abstract: A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

Abstract: A method for manufacturing a resonator that effectively addresses variations in resistivity for each wafer. The method for manufacturing a resonator includes forming a Si oxide film on a surface of a degenerated Si wafer, where the Si oxide film has a thickness set that is based on the doping amount of impurity in the degenerated Si wafer.

Abstract: A piezoelectric element that includes a substrate, a lower electrode layer on the substrate, an intermediate layer on the lower electrode layer, and an upper electrode layer on the intermediate layer. The intermediate layer includes a first piezoelectric layer including an aluminum nitride as a main component thereof and located between the lower electrode layer and the upper electrode layer, a first buffer layer including an aluminum nitride as a main component and located between the first piezoelectric layer and the upper electrode layer, a first intermediate electrode layer located between the first buffer layer and the upper electrode layer, and a second piezoelectric layer located between the first intermediate electrode layer and the upper electrode layer.

Abstract: A gallium nitride structure that includes: a substrate; a gallium nitride layer opposed to the substrate and containing gallium nitride as a main component thereof; and a first electrode between the gallium nitride layer and the substrate. The first electrode includes at least one hafnium layer containing a single metal of hafnium as a main component thereof, and the at least one hafnium layer is in contact with the gallium nitride layer.

Abstract: A dielectric device has a first electrode film having a non-oriented or amorphous structure, a dielectric film provided on the first electrode film and having a preferentially oriented structure, and a second electrode film provided on the dielectric film and having a non-oriented or amorphous structure.

Abstract: A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

Abstract: A method for manufacturing a resonator that effectively addresses variations in resistivity for each wafer. The method for manufacturing a resonator includes forming a Si oxide film on a surface of a degenerated Si wafer, where the Si oxide film has a thickness set that is based on the doping amount of impurity in the degenerated Si wafer.