Abstract: There is provided an optical control element in which non-guided light is prevented from entering into an optical waveguide and which is excellent in optical properties, such as optical modulation properties. A media processor, such as a CD publisher, having a function as a media library. An optical control element includes: a substrate formed of a material having an electro-optical effect; and an optical waveguide formed on a top or bottom surface of the substrate. The optical waveguide has a modulation region b (s) and non-modulation regions a and c along the propagating direction of a light wave propagating through the optical waveguide. In the case when the modulation region is configured to include a single optical waveguide, propagation constants ?0 to ?3 of optical waveguides in the modulation region and the non-modulation region adjacent to each other are set to different values in the modulation region and the non-modulation region.

Abstract: There is provided an optical control element in which non-guided light is prevented from entering into an optical waveguide and which is excellent in optical properties, such as optical modulation properties. a media processor, such as a CD publisher, having a function as a media library. An optical control element includes: a substrate formed of a material having an electro-optical effect; and an optical waveguide formed on a top or bottom surface of the substrate. The optical waveguide has a modulation region b (s) and non-modulation regions a and c along the propagating direction of a light wave propagating through the optical waveguide. In the case when the modulation region is configured to include a single optical waveguide, propagation constants ?0 to ?3 of optical waveguides in the modulation region and the non-modulation region adjacent to each other are set to different values in the modulation region and the non-modulation region.

Abstract: To provide a traveling-wave-type optical modulator and a method of adjusting the same, in which an occurrence of a jitter can be suppressed when an optical modulator is driven by using a driver, and, in particular, to provide a traveling-wave-type optical modulator and a method of adjusting the same, in which a degree of freedom is improved when combining the driver and the traveling-wave-type optical modulator and an occurrence of the jitter can be effectively suppressed even after combining the driver and the traveling-wave-type optical modulator.

Abstract: An optical modulator capable of efficiently separating radiation light and propagation light from each other or removing the radiation light in the optical modulator to suppress loss of the optical modulator and deterioration of an extinction ratio, including a thin plate of a material having an electrooptic effect and a thickness of 20 ?m or less; an optical waveguide formed in a top surface or a bottom surface of the thin plate; and a modulation electrode formed in the top surface of the thin plate to modulate light which propagates in the optical waveguide, the optical waveguide has an optical junction portion in which a plurality of optical waveguide portions are joined together and, for shielding a portion of radiation light radiated from the optical junction portion, a concave portion or through-hole in the thin plate.

Abstract: To provide a traveling-wave-type optical modulator and a method of adjusting the same, in which an occurrence of a jitter can be suppressed when an optical modulator is driven by using a driver, and, in particular, to provide a traveling-wave-type optical modulator and a method of adjusting the same, in which a degree of freedom is improved when combining the driver and the traveling-wave-type optical modulator and an occurrence of the jitter can be effectively suppressed even after combining the driver and the traveling-wave-type optical modulator.

Abstract: Provided is an optical modulator capable of efficiently separating radiation light and propagation light from each other or removing the radiation light in the optical modulator to suppress loss of the optical modulator and deterioration of an extinction ratio. In the optical modulator including a thin plate made of a material having an electrooptic effect and having a thickness of 20 ?m or less; an optical waveguide formed in a top surface or a bottom surface of the thin plate; and a modulation electrode which is formed in the top surface of the thin plate to modulate light which propagates in the optical waveguide, the optical waveguide has an optical junction portion in which a plurality of optical waveguide portions are joined together and a shielding means for shielding a portion of radiation light radiated from the optical junction portion.

Abstract: A first branched optical waveguide and a second branched optical waveguide, to constitute a Mach-Zehnder type optical waveguide, are formed at the surface of a substrate. A first ground electrode, a signal electrode and a second ground electrode are provided on a buffer layer formed on the substrate. The second ground electrode is partially cut away and divided, to form a ditch therein, so that the modulating electrode composed of the signal electrode, the first and the second ground electrodes are substantially symmetrized on the center line between the first and the second optical waveguides. Then, the ratio (d2/d1) of the distance d2 between the signal electrode and the second branched optical waveguide to the distance d1 between the signal electrode and the first electrode is set within 3.5–7.5.

Abstract: A first branched optical waveguide and a second branched optical waveguide, to constitute a Mach-Zehnder type optical waveguide, are formed at the surface of a substrate. A first ground electrode, a signal electrode and a second ground electrode are provided on a buffer layer formed on the substrate. The second ground electrode is partially cut away and divided, to form a ditch therein, so that the modulating electrode composed of the signal electrode, the first and the second ground electrodes are substantially symmetrized on the center line between the first and the second optical waveguides. Then, the ratio (d2/d1) of the distance d2 between the signal electrode and the second branched optical waveguide to the distance d1 between the signal electrode and the first electrode is set within 3.5-7.5.

Abstract: An optical waveguide modulator 40 has a substrate 1 made of a material with an electrooptic effect, an optical waveguide 2 to guide a lightwave 2, a travelling wave-type signal electrode 3 and the ground electrodes 4 to control the lightwave. Moreover, it has a buffer layer 6, at least a part thereof being embedded in the superficial layer of the substrate 1, having a larger width “W” than a width “&ohgr;” of the travelling wave-type signal electrode 3 only under the signal electrode 3 and its nearby part.

Abstract: A first branched optical waveguide and a second branched optical waveguide, to constitute a Mach-Zehnder type optical waveguide, are formed at the surface of a substrate. A first ground electrode, a signal electrode and a second ground electrode are provided on a buffer layer formed on the substrate. The second ground electrode is partially cut away and divided, to form a ditch therein, so that the modulating electrode composed of the signal electrode, the first and the second ground electrodes are substantially symmetrized on the center line between the first and the second optical waveguides. Then, the ratio (d2/d1) of the distance d2 between the signal electrode and the second branched optical waveguide to the distance d1 between the signal electrode and the first electrode is set within 3.5-7.5.

Abstract: An improved optical waveguide device having an optical waveguide for guiding a lightwave comprises, on a surface of a substrate having an electrooptical effect, at least a pair of electrodes composed of a hot electrode and a ground electrode which controls a guided lightwave, a buffer layer formed between the electrodes and the optical waveguide; further comprising an antistatic film which is formed on an upper surface of the buffer layer such that it comes into contact only with the hot electrode.

Abstract: An optical modulator including a substrate made of lithium niobate having an electrooptical effect, first and second optical waveguides formed in the substrate by effecting a thermal diffusion of titanium into a surface of the substrate, a buffer layer formed on the surface of the substrate, a hot electrode provided on the buffer layer and having a width W.sub.e not larger than a width W.sub.f of the optical waveguide, first and second ground electrodes provided on the buffer layer such that these ground electrodes are symmetrical with respect to the hot electrode, and an electric field adjusting region having a width not smaller than that of the hot electrode is provided between the buffer layer and the hot electrode. First and second ground side electric field adjusting main- and sub-regions may be provided between the buffer layer and the first and second ground electrodes, respectively.