Abstract: A filter device includes a laminate body, plate electrodes, resonators, and shield conductors. The plate electrodes are provided in the laminate body and are spaced apart from each other in a lamination direction. The resonators are between the plate electrodes and extend in a first direction. The shield conductors are on respective side surfaces of the laminate body, and connected to the plate electrodes. The resonators are within the laminate body and aligned in a second direction. The resonators each include a first end connected to the shield conductor and a second end spaced apart from the shield conductor. The resonator includes conductors laminated in the lamination direction. When the resonator is viewed in plan from the first direction, the conductors each include a first region including an end portion of the conductor and having a thickness greater than other portions of the conductor.

Abstract: A filter includes a multilayer body, plate electrodes, resonators, shield conductors, and connecting conductors. The multilayer body includes dielectric layers. The plate electrodes are spaced apart from one another in the multilayer body in a lamination direction thereof. The resonators are between the plate electrodes and extend in a first direction orthogonal or substantially orthogonal to the lamination direction. The shield conductors are on lateral surfaces of the multilayer body and are connected to the plate electrodes. The connecting conductors connect the resonators to the plate electrodes. The resonators are side by side in a second direction in the multilayer body. The resonators each include first and second ends. The first ends are connected to the shield conductor, and the second ends are spaced away from the shield conductor.

Abstract: This optical semiconductor element includes: a substrate; a first ridge formed on the substrate and having a first first-conductivity-type cladding layer, a first core layer, a first second-conductivity-type cladding layer, and a first contact layer in this order from a lower side, with first ridge grooves provided on both lateral sides of the first ridge; and a first electrode formed in contact with the first contact layer, on the first ridge, without spreading to the first ridge grooves, the first electrode including a first solder layer.

Abstract: A distributed constant filter includes a resonator that is not grounded and a first ground electrode. The first ground electrode faces the resonator in a first direction (Z). The resonator is a distributed constant line resonator. The resonator includes a plurality of distributed constant lines and a via conductor. The plurality of distributed constant lines are arranged in layers in the first direction (Z). The via conductor extends in the first direction (Z). Each of the plurality of distributed constant lines is connected to the via conductor only at one end portion of both end portions of the distributed constant line.

Abstract: A dielectric resonator includes a dielectric substrate, a distributed element, and a shield conductor portion. The distributed element extends in the X-axis direction inside the dielectric substrate. The shield conductor portion is on a surface of the dielectric substrate and winds around the distributed element when the distributed element is viewed from the X-axis direction in plan view. One end of the distributed element is not connected to the shield conductor portion. The distributed element includes a plurality of conductors.

Abstract: A dielectric resonator includes a dielectric block, an external conductor, and wall-surface conductors. The dielectric block has a rectangular parallelepiped shape including a first surface and a second surface opposed to each other. The dielectric block includes a through hole extending from the first surface to the second surface. The external conductor is disposed on an outer surface of the dielectric block. The wall-surface conductors are disposed on a wall surface defining the through hole. The wall-surface conductor includes a first portion of the through hole adjacent to the first surface and a second portion of the through hole adjacent to the second surface. The first and second portions of the wall-surface conductors are separated by a separation distance.

Abstract: A dielectric resonator includes a dielectric block, an external conductor, and wall-surface conductors. The dielectric block has a rectangular parallelepiped shape including a first surface and a second surface opposed to each other. The dielectric block includes a through hole extending from the first surface to the second surface. The external conductor is disposed on an outer surface of the dielectric block. The wall-surface conductors are disposed on a wall surface defining the through hole. The wall-surface conductor includes a first portion of the through hole adjacent to the first surface and a second portion of the through hole adjacent to the second surface. The first and second portions of the wall-surface conductors are separated by a separation distance.

Abstract: A filtering device includes at least one dielectric resonant element, which includes a dielectric block, an outer conductor, and an inner conductor, a terminal disposed in a through hole of the dielectric resonant element from a front surface, a plate-shaped circuit element electrically coupled with the at least one dielectric resonant element via the terminal, and a substrate on which the at last one dielectric resonant element and the plate-shaped circuit element are mounted. The outer conductor is disposed so as to cover the back surface besides the peripheral surface of the dielectric block. The first end surface of the dielectric block includes a first electrode-free portion that electrically isolates the inner conductor from the outer conductor, and a second electrode-free portion that electrically isolates the inner conductor from the outer conductor.

Abstract: A variable filter circuit includes a serial arm connected between ports (P1-P2), a parallel arm having a resonator connected in series between ports (P1-P3), and another parallel arm having another resonator connected in series between ports (P2-P3). The serial arm includes a capacitor connected between the ports (P1-P2), and the parallel arms include variable capacitances connected in series to the resonators.

Abstract: A variable filter circuit includes a serial arm connected between ports (P1-P2), a parallel arm having a resonator connected in series between ports (P1-P3), and another parallel arm having another resonator connected in series between ports (P2-P3). The serial arm includes a capacitor connected between the ports (P1-P2), and the parallel arms include variable capacitances connected in series to the resonators.

Abstract: A filtering device includes at least one dielectric resonant element, which includes a dielectric block, an outer conductor, and an inner conductor, a terminal disposed in a through hole of the dielectric resonant element from a front surface, a plate-shaped circuit element electrically coupled with the at least one dielectric resonant element via the terminal, and a substrate on which the at last one dielectric resonant element and the plate-shaped circuit element are mounted. The outer conductor is disposed so as to cover the back surface besides the peripheral surface of the dielectric block. The first end surface of the dielectric block includes a first electrode-free portion that electrically isolates the inner conductor from the outer conductor, and a second electrode-free portion that electrically isolates the inner conductor from the outer conductor.

Abstract: A back-surface-incidence semiconductor light element includes: a semiconductor substrate of a first conductivity type; a first semiconductor layer of a first conductivity type on the semiconductor substrate; a light absorbing layer on the first semiconductor layer; a second semiconductor layer on the light absorbing layer; and an impurity diffusion region of a second conductivity type in a portion of the second semiconductor layer. A region including a p-n junction between the first semiconductor layer and the impurity diffusion region, and extending through the light absorbing layer, is a light detecting portion that detects light incident on a back surface of the semiconductor substrate. A groove in the back surface of the semiconductor substrate surrounds the light detecting portion, as viewed in plan.

Abstract: A back-surface-incidence semiconductor light element includes: a semiconductor substrate of a first conductivity type; a first semiconductor layer of a first conductivity type on the semiconductor substrate; a light absorbing layer on the first semiconductor layer; a second semiconductor layer on the light absorbing layer; and an impurity diffusion region of a second conductivity type in a portion of the second semiconductor layer. A region including a p-n junction between the first semiconductor layer and the impurity diffusion region, and extending through the light absorbing layer, is a light detecting portion that detects light incident on a back surface of the semiconductor substrate. A groove in the back surface of the semiconductor substrate surrounds the light detecting portion, as viewed in plan.

Abstract: A band-elimination filter (BEF) that includes a coaxial dielectric resonator block, a substrate, and first, second, and third inductance elements. The coaxial dielectric resonator block includes inner conductors and an outer conductor, and forms coaxial dielectric resonators. The first inductance element is between a signal transmission path connected to one of the coaxial dielectric resonators via a series resonant capacitor and a signal transmission path connected to the other one of the coaxial dielectric resonators via a series resonant capacitor. The second inductance element is between one end of the first inductance element and the ground, and the third inductance elements is between the other end of the first inductance element and the ground.

Abstract: In a semiconductor laser device a dual wavelength semiconductor laser chip is joined onto a submount, junction down, to reduce built-in stress produced between the laser chip and the submount and to decrease polarization angles of the two respective lasers. SnAg solder is used to join the dual wavelength semiconductor laser chip onto the submount. When joining, with respect to each of the two lasers, a ratio of a distance between the center line of a waveguide and an end, placed at a lateral side of the laser chip, of a portion joining the laser chip and the submount, to a distance between the center line of the waveguide and another end, placed toward the center of the laser chip, of the portion joining the laser chip and the submount, falls within a range of 0.69 to 1.46.

Abstract: A semiconductor laser is provided which emits laser light in which the intensity center of the far-field pattern in the horizontal direction does not vary with variation of the optical output and in which the shape of the far-field pattern in the horizontal direction is stable. The width of trenches is determined so that the magnitude (E1) of the electric field at the center of a ridge and the magnitude (E2) of the electric field at the edges of the trenches provide a ratio E1/E2 that is larger than 0.0001 and smaller than 0.01. In a semiconductor laser with a double-channel ridge structure, layers having a larger equivalent refractive index than the trenches exist outside the trenches.

Abstract: A semiconductor laser is provided which emits laser light in which the intensity center of the far-field pattern in the horizontal direction does not vary with variation of the optical output and in which the shape of the far-field pattern in the horizontal direction is stable. The width of trenches is determined so that the magnitude (E1) of the electric field at the center of a ridge and the magnitude (E2) of the electric field at the edges of the trenches provide. a ratio E1/E2 that is larger than 0.0001 and smaller than 0.01. In a semiconductor laser with a double-channel ridge structure, layers having a larger equivalent refractive index than the trenches exist outside the trenches.

Abstract: A method of manufacturing a semiconductor laser includes sequentially forming a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer on top of one another on a semiconductor substrate; forming a ridge in the second conductivity type semiconductor layer; forming a first insulating film on the second conductivity type semiconductor layer at a first temperature; forming a second insulating film on the first insulating film at a second temperature, lower than the first temperature; and forming an electrode on the second insulating film.

Abstract: A dielectric filter with an ultra hetero-axial structure is provided with open end-face electrodes. By increasing the capacitance between each open end-face electrode and an external conductor greater than that generated between the open end-face electrodes adjacent to each other, the inductive coupling between two resonators due to neighboring resonator holes is increased.

Abstract: A semiconductor laser is provided which emits laser light in which the intensity center of the far-field pattern in the horizontal direction does not vary with variation of the optical output and in which the shape of the far-field pattern in the horizontal direction is stable. The width of trenches is determined so that the magnitude (E1) of the electric field at the center of a ridge and the magnitude (E2) of the electric field at the edges of the trenches provide a ratio E1/E2 that is larger than 0.0001 and smaller than 0.01. In a semiconductor laser with a double-channel ridge structure, layers having a larger equivalent refractive index than the trenches exist outside the trenches.