Abstract: The present invention discloses an electro-optic waveguide device such as a modulator. The device has an electro-optic substrate having optical waveguides within the substrate at or near an upper surface. A buffer layer is formed on the top surface of the electro-optic substrate. A novel block layer is formed on the buffer layer surface, which can suppress or lessen an unwanted occurrence of chemical reactions at or near the surface of the buffer layer. A charge bleed off layer is formed on the block layer, which has a certain amount of electrical conductivity to bleed off any electrical charges generated on or in the electro-optic waveguide device. Electrodes are on the charge bleed off layer, which can provide electrical signals to the optical waveguides through the buffer layer, the block layer, and the charge bleed off layer.

Abstract: An optical modulator which has substantially low loss and has an improvement in voltage reduction is disclosed having an electro-optic lithium niobate substrate. The substrate has first, second and third ridges extending along its surface. Extending along the first and second ridges are first and second waveguides. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. A second section of the slotted extends parallel to and adjacent to the first section on the third ridge. In summary, this invention provides a slotted ground electrode wherein a slot is formed in the substrate between the slotted electrode.

Abstract: The present invention discloses an electro-optic waveguide device such as a modulator. The device has an electro-optic substrate having optical waveguides within the substrate at or near an upper surface. A buffer layer is formed on the top surface of the electro-optic substrate. A novel block layer is formed on the buffer layer surface, which can suppress or lessen an unwanted occurrence of chemical reactions at or near the surface of the buffer layer. A charge bleed off layer is formed on the block layer, which has a certain amount of electrical conductivity to bleed off any electrical charges generated on or in the electro-optic waveguide device. Electrodes are on the charge bleed off layer, which can provide electrical signals to the optical waveguides through the buffer layer, the block layer, and the charge bleed off layer.

Abstract: An optical modulator which has substantially low loss and has an improvement in voltage reduction is disclosed having an electro-optic lithium niobate substrate. The substrate has first, second and third ridges extending along its surface. Extending along the first and second ridges are first and second waveguides. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. A second section of the slotted extends parallel to and adjacent to the first section on the third ridge. In summary, this invention provides a slotted ground electrode wherein a slot is formed in the substrate between the slotted electrode.

Abstract: A first film (8) is formed between a substrate (1) and a signal electrode (3); ground electrodes (5) and (6) which constitute an optical waveguide device (10), and a second film (9) is formed between the substrate (1) and a signal electrode (4); ground electrodes (6) and (7). An optical phase modulator (10A) is composed of the substrate (1), an optical waveguide (2), the signal electrode (3), the ground electrodes (5) and (6), and the first film (8). An optical intensity modulator (10B) is composed of the substrate (1), the optical waveguide (2), the signal electrode (4), the ground electrodes (6) and (7), and the second film (9). The optical waveguide device (10) is composed of the optical phase modulator (10A) and the optical intensity modulator (10B), which are integrated monolithically.

Abstract: There is provided a high performance optical waveguide type optical modulator with excellent long term reliability, in which contamination of the buffer layer in a forming process of a signal field adjustment region on the buffer layer by a lift-off method or an etching method, is prevented and DC drift thus suppressed.

Abstract: An optical waveguide is formed on a substrate made of a material with an electro-optic effect. Then, an intermediate layer is fabricated, on the main surface of the substrate, by a dielectric material selected from the group consisting of AOx, B2Oy, COz (A: divalent element, B: trivalent element, C: quadrivalent element, 0<x<1, 0<y<3, 0<z<2, O: oxygen). Then, a metal-cladding type optical polarizer is fabricated on the intermediate layer and the optical waveguide. A buffer layer is formed and partially removed by non-reactive dry-etching to form a first opening. Subsequently, a metal-cladding type optical polarizer is fabricated inside the first opening, and a signal electrode and a ground electrode, constituting a modulation electrode, are fabricated on the buffer layer.

Abstract: A first film (8) is formed between a substrate (1) and a signal electrode (3); ground electrodes (5) and (6) which constitute an optical waveguide device (10), and a second film (9) is formed between the substrate (1) and a signal electrode (4); ground electrodes (6) and (7). An optical phase modulator (10A) is composed of the substrate (1), an optical waveguide (2), the signal electrode (3), the ground electrodes (5) and (6), and the first film (8). An optical intensity modulator (10B) is composed of the substrate (1), the optical waveguide (2), the signal electrode (4), the ground electrodes (6) and (7), and the second film (9). The optical waveguide device (10) is composed of the optical phase modulator (10A) and the optical intensity modulator (10B), which are integrated monolithically.

Abstract: There is provided a high performance optical waveguide type optical modulator with excellent long term reliability, in which contamination of the buffer layer in a forming process of a signal field adjustment region on the buffer layer by a lift-off method or an etching method, is prevented and DC drift thus suppressed.

Abstract: An electro-optic element comprising a ferroelectric substrate comprising a single crystal having an electro-optic effect, in which an optical waveguide is formed by thermal diffusion of titanium in a main face, and in which an axis in which said electro-optic effect is induced is parallel to said main face; a heat treated buffer layer provided on said ferroelectric substrate on a side in which said optical waveguides are formed; electrodes provided on a part of the buffer layer; and a protective film for preventing contamination of the buffer layer provided on at least the region of the buffer layer on which the electrodes are not formed.

Abstract: The object of the present invention is to provide a light limiter which can control the generation of an optical surge, comprises few components, and has high reliability; in order to achieve the object, the light limiter of the present invention comprise a parametric amplification element parametrically amplifying an input signal light, and a wavelength selection element removing a wavelength component, excepting a specified wavelength, from among the signal light output from said parametric amplification element.

Abstract: An optical waveguide is formed on a substrate made of a material with an electro-optic effect. Then, an intermediate layer is fabricated, on the main surface of the substrate, by a dielectric material selected from the group consisting of AOx, B2Oy, COz (A: divalent element, B: trivalent element, C: quadrivalent element, 0<x<1, 0<y<3, 0<z<2, O: oxygen). Then, a metal-cladding type optical polarizer is fabricated on the intermediate layer and the optical waveguide. A buffer layer is formed and partially removed by non-reactive dry-etching to form a first opening. Subsequently, a metal-cladding type optical polarizer is fabricated inside the first opening, and a signal electrode and a ground electrode, constituting a modulation electrode, are fabricated on the buffer layer.

Abstract: The object of the present invention is to provide a light limiter which can control the generation of an optical surge, comprises few components, and has high reliability; in order to achieve the object, the light limiter of the present invention comprise a parametric amplification element parametrically amplifying an input signal light, and a wavelength selection element removing a wavelength component, excepting a specified wavelength, from among the signal light output from said parametric amplification element.

Abstract: The object of the present invention is to provide a light limiter which can control the generation of an optical surge, comprises few components, and has high reliability; in order to achieve the object, the light limiter of the present invention comprise a parametric amplification element parametrically amplifying an input signal light, and a wavelength selection element removing a wavelength component, excepting a specified wavelength, from among the signal light output from said parametric amplification element.

Abstract: The optical fuse of the present invention comprises: at least one light heatable portion for receiving an incident beam, and at least one thermally sensitive degradable portion with transparency and reflectivity, positioned in contact with the light heatable portion. The light heatable portion contains a light heatable material which generates heat depending on a specified light intensity of the incident beam. The thermally sensitive degradable portion contains a thermally sensitive degradable material which loses or reduces its transparency and reflectivity, depending on the heat generated by the light heatable portion when the light intensity of the incident beam exceeds a threshold value.

Abstract: A light intensity attenuator and attenuating method is provided, by which a pulse-shaped optical surge can be attenuated and an optical signal component using desired light intensity can be output by using a simpler structural arrangement, and without using many optical components and circuits. In this method, an optical signal including a pulse-shaped optical surge component is received, and the optical signal is again output after the light intensity of the surge component is attenuated by a desired amount.

Abstract: An optical element-optical fiber composite structure having a high resistance of the optical fiber to breakage due to cyclical change in temperature, includes a package structure having a main container, side containers attached to the main container and sleeves through which a main chamber of the main container is connected to side chambers of the side containers; an optical element housed in the main chamber; and optical fibers introduced into the main chamber through the side chambers and the sleeves and connected to the optical element.

Abstract: An optical element-optical fiber composite structure having a high resistance of the optical fiber to breakage due to cyclical change in temperature, includes a package structure having a main container, side containers attached to the main container and sleeves through which a main chamber of the main container is connected to side chambers of the side containers; an optical element housed in the main chamber; and optical fibers introduced into the main chamber through the side chambers and the sleeves and connected to the optical element.

Abstract: An optical waveguide device usable as an optical wave-modulator and having a reduced DC drift includes a LiNbO.sub.3 substrate, an optical waveguide formed in a front surface portion of the substrate, a dielectric layer covering the front surface of the substrate and the optical waveguide surface, and an electrode system arranged on the dielectric layer, the dielectric layer comprising a matrix component consisting of an amorphous SiO.sub.2 and a doping element component consisting of Li and/or Nb; and having a refractive index lower than that of the amorphous SiO.sub.2 matrix free from the doping element component.

Abstract: A jacket layer of a jacketed optical fiber is cut by a cutting method and apparatus in which (A) a terminal portion of a jacketed optical fiber is straightened and grasped by a fiber holder, and (B) a blade device having (a) a pair of cutting blades and (b) a blade holder in which device cutting edges of the blades are arranged in such a manner that the edges are opposite to each other through a gap left therebetween and are on one and the same plane, the straightened portion of the jacketed optical fiber extends at a substantially right angle to the plane, and a center line of the gap between the cutting edges intersects an axis of the straightened portion of the jacketed optical fiber, and is moved in at least one direction at a substantially right angle to the axis of the straightened portion of the jacketed optical fiber to cut the secondary coating layer at a depth equal to or larger than the thickness of the secondary coating layer but smaller than the total thickness of the primary and secondary coatin