Abstract: An optical modulator has an optical modulation element including optical waveguides and a housing that accommodates the optical modulation element. The housing has a bottom surface wall having a quadrilateral shape in a plan view, first and second long side walls that are connected to two opposite edges of the bottom surface wall, and first and second short side walls, shorter than the long side walls, and connected to two other opposite edges of the bottom surface wall. The optical modulation element is accommodated in a space surrounded by the bottom surface wall and the side walls. The second long side wall has a wall thickness that is equal to or larger than that of the first long side wall, and at least one of the first and second short side walls has a wall thickness that is thinner than that of the first long side wall.

Abstract: An optical modulator includes a relay substrate having signal conductor patterns that connect input signal terminals and signal electrodes of an optical modulation element and ground conductor patterns, and a housing that accommodates the optical modulation element and the relay substrate. Regarding at least one signal conductor pattern, the two ground conductor patterns sandwiching the signal conductor pattern are formed in an asymmetrical shape in a plan view in a rectangular connection area including a signal connection portion at which the signal conductor pattern and the input signal terminal are connected. The connection area is centered on the at least one signal conductor pattern in a width direction, and has a width equal to a distance to the nearest adjacent signal conductor pattern and a height equal to a distance from an end of the signal connection portion farthest from a signal input side to the signal input side.

Abstract: An optical modulator includes: an optical modulation element that is configured to generate two modulated light beams, each of which is modulated by two sets of electrical signals, and that includes a plurality of signal electrodes; a plurality of signal input terminals, each of which inputs an electrical signal; a relay substrate on which a plurality of signal conductor patterns and a plurality of ground conductor patterns are formed, the relay substrate being configured to propagate the two sets of electrical signals by two pairs of the adjacent signal conductor patterns; and a housing, in which the at least two signal conductor patterns including at least one parts mounting part including electrical circuit elements are configured such that first signal propagation directions, which are signal propagation directions at the parts mounting parts, are different from each other.

Abstract: An optical modulator includes: an optical modulation element including a plurality of signal electrodes and generating two modulated light beams, each of which is modulated by two sets of electrical signals; a plurality of signal input terminals, each of which inputs an electrical signal; a relay substrate on which a plurality of signal and ground conductor patterns are formed, the relay substrate propagating the two sets of electrical signals by two pairs of the adjacent signal conductor patterns; and a housing, in which at least one signal conductor pattern includes at least one component mounting portion including at least a parallel circuit of a resistor and a capacitor, and the relay substrate includes a metal body connected on the ground conductor pattern or a substrate removal portion that sandwiches a portion of the signal conductor pattern downstream of the component mounting portion along a propagation direction of the electrical signal.

Abstract: An optical modulator includes a relay substrate having signal conductor patterns that connect signal input terminals and signal electrodes of an optical modulation element and ground conductor patterns, and a housing, in which the signal conductor pattern includes a component mounting portion including an electrical circuit element. Two ground conductor patterns sandwiching the signal conductor pattern are formed in an asymmetrical shape in a plan view within a component mounting area having a square shape in the plan view centered on the component mounting portion. A direction of a side of the component mounting area having the square shape is same as the extending direction of the signal conductor pattern and a length of a side of the component mounting area is equal to a distance from a center of the component mounting portion to a portion on an adjacent signal conductor pattern closest to the center.

Abstract: An optical waveguide element including a substrate, an optical waveguide formed on the substrate, and an electrode for controlling a light wave propagating through the optical waveguide, in which the optical waveguide and the electrode have an intersection in which the optical waveguide and the electrode intersect with each other, and at the intersection, the electrode has a multilayer structure including a plurality of metal layers made of a metal material, and a resin layer made of a resin material is formed between the electrode and the substrate.

Abstract: In an optical modulator, high frequency characteristics are improved and the stability thereof is improved. An optical modulator includes: an optical element substrate that includes an optical waveguide and a plurality of electrodes that control light waves propagating through the optical waveguide; and a package case that houses the optical element substrate, in which a plurality of signal input terminals, respectively electrically connected to the plurality of electrodes, are provided on the bottom surface of the package case, and the plurality of signal input terminals respectively electrically connected to the plurality of electrodes provided on the optical element substrate are divided and disposed on the sides facing each other with the optical element substrate interposed therebetween.

Abstract: An initial change and a secular change in an optical characteristic and a high frequency characteristic in a case where an optical modulator is mounted in a package of an optical transmission apparatus are suppressed while improving a space utilization rate in the package of the optical transmission apparatus. An optical modulator that is electrically connected to an electric circuit configured on a circuit board, includes: a package that houses an optical modulation element; and a signal input part or the like for inputting an electric signal for causing the optical modulation element to perform an modulation operation from the electric circuit, in which the package has, on a part of a bottom surface facing the circuit board, a first protrusion portion protruding from the bottom surface, and the signal input part is provided on an upper surface of the first protrusion portion.

Abstract: An optical modulator that can effectively dissipate heat generated from the inside includes: an optical modulation element which includes an optical waveguide and a radio frequency electrode for controlling light waves propagating through the optical waveguide; a termination resistor electrically connected to the radio frequency electrode; a termination resistor board on which the termination resistor is disposed; and a package case, which houses the optical modulation element and the termination resistor board, in which a plurality of protrusion portions are formed on one external surface of the package case, and at least one of the protrusion portions is formed at a position on the external surface of the package case, which faces a position inside the package case where the termination resistor board is disposed with the package case in between.

Abstract: An optical waveguide element is provided to effectively reduce an optical absorption loss of waveguide light which may occur at an intersecting part between an optical waveguide and an electrode without causing deterioration in optical characteristics and degradation of long-term reliability of the optical waveguide element. The optical waveguide element includes an optical waveguide formed in a substrate, and an electrode controlling optical waves propagated in the optical waveguide and having an intersecting part intersecting the optical waveguide thereabove. A portion of a resin layer is provided between the optical waveguide and the electrode in a portion of the substrate including the intersecting part. A corner of the resin layer on a side of the electrode is constituted to be a curve in a cross section in an extending direction of the electrode.

Abstract: An optical modulator includes an optical modulation element having a plurality of signal electrodes, a plurality of signal input terminals, a relay substrate on which a plurality of signal conductor patterns that electrically connect the signal input terminals and the signal electrodes and a plurality of ground conductor patterns are formed, and a housing. A signal input side and signal output side of the relay substrate face each other in a plan view, and electromagnetic wave propagation suppressing units that are made of a material that absorbs electromagnetic waves and have a height protruding from a surface of the relay substrate are provided, along at least one side of an end portion of the signal input side and an end portion of the signal output side in the plan view.

Abstract: An optical modulator includes an optical modulation element including an optical waveguide formed on a substrate and a housing that accommodates the optical modulation element, the housing has a bottom surface wall having a quadrilateral shape in a plan view, first and second long side walls that are connected to two opposite edges of the bottom surface wall, and first and second short side walls that are shorter than the first and second long side walls and are connected to two other opposite edges of the bottom surface wall. An average wall thickness of the second long side wall is equal to or larger than an average wall thickness of the first long side wall. At least one of the first and second short side walls has an average thickness that is thinner than the average thickness of the first long side wall.

Abstract: An optical modulator including an optical modulation element including an optical waveguide formed on a substrate, and a housing that accommodates the optical modulation element. The housing has a high-thermal resistance portion within at least a part of an optical input and output region. The optical input and output region is an area ranging from an outer surface of a first short side wall to a first end portion of the optical modulation element, and the high-thermal resistance portion having a higher thermal resistance than a portion of the housing other than the optical input and output region.

Abstract: To provide a highly-reliable low-cost small optical modulator in which temperature drift is suppressed and an optical transmission device using the same. An optical modulator including an optical waveguide substrate 1 on which an optical waveguide is formed, a signal electrode which is provided on the optical waveguide substrate and applies an electric field to the optical waveguide, a termination substrate 3 provided with a termination resistor that terminates the signal electrode, and a housing 6 in which the optical waveguide substrate and the termination substrate are mounted, in which, in order to suppress conduction of heat generated from the termination resistor to the optical waveguide substrate through the housing, a groove 8 is formed in the housing 6 between the termination substrate 3 and the optical waveguide substrate 1.

Abstract: An initial change and a secular change in an optical characteristic and a high frequency characteristic in a case where an optical modulator is mounted in a package of an optical transmission apparatus are suppressed while improving a space utilization rate in the package of the optical transmission apparatus. An optical modulator that is electrically connected to an electric circuit configured on a circuit board, includes a package that houses an optical modulation element, in which the package has, on a bottom surface facing the circuit board, a plurality of first protruding bodies protruding from the bottom surface.

Abstract: An optical waveguide element is provided to effectively reduce an optical absorption loss of waveguide light which may occur at an intersecting part between an optical waveguide and an electrode without causing deterioration in optical characteristics and degradation of long-term reliability of the optical waveguide element. The optical waveguide element includes an optical waveguide formed in a substrate, and an electrode controlling optical waves propagated in the optical waveguide and having an intersecting part intersecting the optical waveguide thereabove. A portion of a resin layer is provided between the optical waveguide and the electrode in a portion of the substrate including the intersecting part. A corner of the resin layer on a side of the electrode is constituted to be a curve in a cross section in an extending direction of the electrode.

Abstract: An optical modulator includes an optical modulation element having a plurality of signal electrodes; a housing that houses the optical modulation element; a plurality of signal input terminals each of which inputs an electrical signal to be applied to each of the signal electrodes; and a relay substrate on which a plurality of signal conductor patterns that electrically connect each of the signal input terminals to each of the signal electrodes, and a plurality of ground conductor patterns are formed, in which the relay substrate is housed in the housing, and at least one input side ground conductor pattern extending from at least one of the ground conductor patterns is formed on an input side surface having a side on which an electrical signal output from the signal input terminal is input to the signal conductor pattern as one side.

Abstract: An optical waveguide element including a substrate, an optical waveguide formed on the substrate, and an electrode for controlling a light wave propagating through the optical waveguide, in which the optical waveguide and the electrode have an intersection in which the optical waveguide and the electrode intersect with each other, and at the intersection, the electrode has a multilayer structure including a plurality of metal layers made of a metal material, and a resin layer made of a resin material is formed between the electrode and the substrate.

Abstract: To suppress characteristic fluctuations and or the degradation of long-term reliability attributed to the disposition of a heat-generating electronic component close to an optical modulator.

Abstract: An optical modulator has an optical modulation element including optical waveguides and a housing that accommodates the optical modulation element. The housing has a bottom surface wall having a quadrilateral shape in a plan view, first and second long side walls that are connected to two opposite edges of the bottom surface wall, and first and second short side walls, shorter than the long side walls, and connected to two other opposite edges of the bottom surface wall. The optical modulation element is accommodated in a space surrounded by the bottom surface wall and the side walls. The second long side wall has a wall thickness that is equal to or larger than that of the first long side wall, and at least one of the first and second short side walls has a wall thickness that is thinner than that of the first long side wall.