Abstract: An optical modulator includes: a ferroelectric substrate in which an input optical waveguide, first and second optical waveguides, and an output optical waveguide are formed; a first electrode formed in a vicinity of the first optical waveguide and to which a first DC voltage is applied; a second electrode formed in a vicinity of the second optical waveguide and to which a second DC voltage is applied; a third electrode electrically connected to the first electrode and formed on both sides of the second electrode; and a fourth electrode electrically connected to the second electrode and formed on both sides of the first electrode. A first gap between the first electrode and the fourth electrode is approximately the same as a second gap between the second electrode and the third electrode. A gap between the third electrode and the fourth electrode is 1-5 times greater than the first gap.

Abstract: A substrate is a substrate on which a first optical modulator and a second optical modulator are arranged in parallel along a width direction. A first prism moves, to a side opposite to the second optical modulator along the width direction of the substrate, an optical path of the first output light and the second output light that are obtained by light of the first wavelength being modulated by the first optical modulator. A second prism is arranged at a position away from the first prism along a longitudinal direction of the substrate and moves, to a side opposite to the first modulator along the width direction of the substrate, an optical path of the third output light and the fourth output light that are obtained by the light of the second wavelength being modulated by the second optical modulator.

Abstract: An optical modulator includes: a ferroelectric substrate in which an input optical waveguide, first and second optical waveguides, and an output optical waveguide are formed; a first electrode formed in a vicinity of the first optical waveguide and to which a first DC voltage is applied; a second electrode formed in a vicinity of the second optical waveguide and to which a second DC voltage is applied; a third electrode electrically connected to the first electrode and formed on both sides of the second electrode; and a fourth electrode electrically connected to the second electrode and formed on both sides of the first electrode. A first gap between the first electrode and the fourth electrode is approximately the same as a second gap between the second electrode and the third electrode. A gap between the third electrode and the fourth electrode is 1-5 times greater than the first gap.

Abstract: A substrate is a substrate on which a first optical modulator and a second optical modulator are arranged in parallel along a width direction. A first prism moves, to a side opposite to the second optical modulator along the width direction of the substrate, an optical path of the first output light and the second output light that are obtained by light of the first wavelength being modulated by the first optical modulator. A second prism is arranged at a position away from the first prism along a longitudinal direction of the substrate and moves, to a side opposite to the first modulator along the width direction of the substrate, an optical path of the third output light and the fourth output light that are obtained by the light of the second wavelength being modulated by the second optical modulator.

Abstract: A mach-zehnder optical modulator includes a substrate having electrooptical effect, wherein: the substrate has an inputting waveguide portion, two intermediate waveguide portions, an outputting waveguide portion and a sub optical waveguide portion, the inputting waveguide portion being branched and coupled to the two intermediate waveguide portions, the two intermediate waveguide portions being combined and coupled to the outputting waveguide portion, the sub optical waveguide being provided on at least one side of the outputting optical waveguide portion and having a given distance from the outputting optical waveguide portion, the sub optical waveguide portion guiding an off-light emitted from a combining portion of the two intermediate waveguide portions; and a width of a starting point of the sub optical waveguide portion is larger than the outputting waveguide portion.

Abstract: A mach-zehnder optical modulator includes a substrate having electrooptical effect, wherein: the substrate has an inputting waveguide portion, two intermediate waveguide portions, an outputting waveguide portion and a sub optical waveguide portion, the inputting waveguide portion being branched and coupled to the two intermediate waveguide portions, the two intermediate waveguide portions being combined and coupled to the outputting waveguide portion, the sub optical waveguide being provided on at least one side of the outputting optical waveguide portion and having a given distance from the outputting optical waveguide portion, the sub optical waveguide portion guiding an off-light emitted from a combining portion of the two intermediate waveguide portions; and a width of a starting point of the sub optical waveguide portion is larger than the outputting waveguide portion.

Abstract: A mach-zehnder optical modulator includes a substrate having electrooptical effect, wherein: the substrate has an inputting waveguide portion, two intermediate waveguide portions, an outputting waveguide portion and a sub optical waveguide portion, the inputting waveguide portion being branched and coupled to the two intermediate waveguide portions, the two intermediate waveguide portions being combined and coupled to the outputting waveguide portion, the sub optical waveguide being provided on at least one side of the outputting optical waveguide portion and having a given distance from the outputting optical waveguide portion, the sub optical waveguide portion guiding an off-light emitted from a combining portion of the two intermediate waveguide portions; and a width of a starting point of the sub optical waveguide portion is larger than the outputting waveguide portion.