Abstract: In a bonded substrate according to an embodiment, Euler angles (?1, ?1, ?1) of a first quartz-crystal substrate satisfy 0°??1?2°, 123°??1?128°, and 31°??1?44°, Euler angles (?2, ?2, ?2) of a second quartz-crystal substrate bonded over the first quartz-crystal substrate satisfy 83°??2?95°, 82°??2?95°, and 159°??2?161°, and a thickness of the second quartz-crystal substrate is 0.17 to 0.19 times a wavelength of a surface acoustic wave.

Abstract: In a surface acoustic wave resonator according to an embodiment, a quartz-crystal substrate includes an AT-cut 0° X-propagation first quartz-crystal substrate and a Z-cut second quartz-crystal substrate bonded over the first quartz-crystal substrate. A propagation direction of a surface acoustic wave in the second quartz-crystal substrate is inclined from an X-axis of a crystal by 27 to 33°, 87 to 93°, or 147 to 153°, and a thickness of the second quartz-crystal substrate is 0.2 to 1.0 times a wavelength of the surface acoustic wave.

Abstract: A method of manufacturing a bonded substrate, which has a quartz substrate and a piezoelectric substrate bonded, includes irradiating a bonding surface of the quartz substrate and a bonding surface of the piezoelectric substrate with ultraviolet light under a pressure lower than atmosphere pressure. After the irradiation, the bonding surface of the quartz substrate and the bonding surface of the piezoelectric substrate are brought into contact. And the quartz substrate and the piezoelectric substrate are pressurized in a thickness direction to bond the bonding surfaces.

Abstract: In a surface acoustic wave filter according to an embodiment, a thickness of a piezoelectric crystal substrate bonded over a support substrate made of an oxide crystal is 0.05 to 0.5 ?m, and an odd-order harmonic is used.

Abstract: In a surface acoustic wave resonator according to an embodiment, a quartz-crystal substrate includes an AT-cut 0° X-propagation first quartz-crystal substrate and a Z-cut second quartz-crystal substrate bonded over the first quartz-crystal substrate. A propagation direction of a surface acoustic wave in the second quartz-crystal substrate is inclined from an X-axis of a crystal by 27 to 33°, 87 to 93°, or 147 to 153°, and a thickness of the second quartz-crystal substrate is 0.2 to 1.0 times a wavelength of the surface acoustic wave.

Abstract: Provided is a dual-band resonator which can be downsized further than conventional ones. A dual-band resonator is provided with a first conductor and a second conductor. The first conductor is configured to be folded at a first folding part at the center so that both extensions are in a prescribed direction and adjacent to one another with a prescribed space therebetween, wherein a conductor part closer to one end side than the first folding part and a conductor part closer to the other end side than the first folding part are further folded at second folding parts between the one end and the first folding part and between the other end and the first folding part, respectively, in a direction in which the one end and the other end are apart from each other. The second conductor extends in a prescribed direction contiguously to the first folding part of the first conductor. The first conductor constitutes a half-wavelength resonator, and odd-mode resonance occurs in the first conductor.

Abstract: In a surface acoustic wave filter according to an embodiment, a thickness of a piezoelectric crystal substrate bonded over a support substrate made of an oxide crystal is 0.05 to 0.5 ?m, and an odd-order harmonic is used.

Abstract: An optical modulator, a substrate for an optical modulator, a method of manufacturing an optical modulator, and a method of manufacturing a substrate for an optical modulator that can reduce a propagation loss are provided. An optical modulator 1 according to an embodiment includes: a base substrate 10; a waveguide substrate 20 disposed over the base substrate 10 and including an electro-optic effect; a waveguide 23 formed on the waveguide substrate 20 for performing optical modulation; and an electrode 40 configured to apply a voltage to the waveguide 23. Here, the base substrate 10 and the waveguide substrate 20 are made of the same material, the waveguide 23 is formed inside the waveguide substrate 20, and a refractive index of the waveguide substrate 20 is larger than a refractive index of the base substrate 10.

Abstract: A bonded substrate includes: a quartz substrate cut at an intersection angle with a crystal X-axis; and a piezoelectric substrate laminated on the quartz substrate. Preferably, a cut angle of the quartz substrate has an angle in the range of 85 to 95 degrees with respect to the crystal X-axis. Preferably, the surface acoustic wave propagation direction of the quartz substrate has an angle of 15 to 50 degrees with respect to a crystal Y-axis. Preferably, as a piezoelectric substrate, lithium niobate or lithium tantalate is used. Preferably, the piezoelectric substrate has a thickness h having a relationship of 0.02 to 0.11? with respect to a wavelength ? of a surface acoustic wave.

Abstract: Provided is a dual-band resonator which can be downsized further than conventional ones. A dual-band resonator is provided with a first conductor and a second conductor. The first conductor is configured to be folded at a first folding part at the center so that both extensions are in a prescribed direction and adjacent to one another with a prescribed space therebetween, wherein a conductor part closer to one end side than the first folding part and a conductor part closer to the other end side than the first folding part are further folded at second folding parts between the one end and the first folding part and between the other end and the first folding part, respectively, in a direction in which the one end and the other end are apart from each other. The second conductor extends in a prescribed direction contiguously to the first folding part of the first conductor. The first conductor constitutes a half-wavelength resonator, and odd-mode resonance occurs in the first conductor.

Abstract: A bonded substrate includes a quartz substrate and a piezoelectric substrate which is bonded on the quartz substrate and on which a surface acoustic wave propagates, wherein the quartz substrate and the piezoelectric substrate are bonded by covalently coupling at a bonding interface, and an orientation of the quartz substrate and an orientation of the piezoelectric substrate intersect with each other on an orthogonal direction side or in the range of 65 degrees to 115 degrees in a bonding surface direction.

Abstract: A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod having a circular cross section is provided in the space above the respective stubs and another dielectric rod having a circular cross section is provided in the space above the half-wavelength resonator protrusions.

Abstract: An optical modulator, a substrate for an optical modulator, a method of manufacturing an optical modulator, and a method of manufacturing a substrate for an optical modulator that can reduce a propagation loss are provided. An optical modulator 1 according to an embodiment includes: a base substrate 10; a waveguide substrate 20 disposed over the base substrate 10 and including an electro-optic effect; a waveguide 23 formed on the waveguide substrate 20 for performing optical modulation; and an electrode 40 configured to apply a voltage to the waveguide 23. Here, the base substrate 10 and the waveguide substrate 20 are made of the same material, the waveguide 23 is formed inside the waveguide substrate 20, and a refractive index of the waveguide substrate 20 is larger than a refractive index of the base substrate 10.

Abstract: A method of manufacturing a bonded substrate, which has a quartz substrate and a piezoelectric substrate bonded, includes irradiating a bonding surface of the quartz substrate and a bonding surface of the piezoelectric substrate with ultraviolet light under a pressure lower than atmosphere pressure. After the irradiation, the bonding surface of the quartz substrate and the bonding surface of the piezoelectric substrate are brought into contact. And the quartz substrate and the piezoelectric substrate are pressurized in a thickness direction to bond the bonding surfaces.

Abstract: There is provided a bonded substrate including: a quartz substrate; and a piezoelectric substrate which is bonded on the quartz substrate and on which a surface acoustic wave propagates, wherein the quartz substrate and the piezoelectric substrate are bonded at a bonding interface through covalent bonding, and a surface acoustic wave element having a higher phase velocity and a higher electromechanical coupling factor than conventional one is obtained by disposing an interdigital electrode on a principal surface of the piezoelectric substrate.

Abstract: A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod having a circular cross section is provided in the space above the respective stubs and another dielectric rod having a circular cross section is provided in the space above the half-wavelength resonator protrusions.

Abstract: A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod having a circular cross section is provided in the space above the respective stubs and another dielectric rod having a circular cross section is provided in the space above the half-wavelength resonator protrusions.

Abstract: There is provided a bonded substrate including: a quartz substrate; and a piezoelectric substrate which is bonded on the quartz substrate and on which a surface acoustic wave propagates, wherein the quartz substrate and the piezoelectric substrate are bonded at a bonding interface through covalent bonding, and a surface acoustic wave element having a higher phase velocity and a higher electromechanical coupling factor than conventional one is obtained by disposing an interdigital electrode on a principal surface of the piezoelectric substrate.

Abstract: A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod circular in cross section is provided in the space above the respective stubs, and another dielectric rod circular in cross section is provided in the space above the half-wavelength resonator protrusions.

Abstract: A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod circular in cross section is provided in the space above the respective stubs, and another dielectric rod circular in cross section is provided in the space above the half-wavelength resonator protrusions.