Abstract: The invention provides a semiconductor optical modulator including a two-step mesa optical waveguide having a first clad layer (101); a mesa-like core layer (102) formed over the first clad layer (101); and a second clad layer (103) formed into a mesa shape over the core layer (102), and having a mesa width smaller than that of the core layer (102). The two-step mesa optical waveguide includes a multi-mode optical waveguide region to which an electric field is applied or into which an electric current is injected, and a single-mode optical waveguide region to which the electric field is not applied and into which the electric current is not injected. When the mesa width of the core layer in the multi-mode optical waveguide region is defined as Wmesa1, and the mesa width of the core layer in the single-mode optical waveguide region is defined as Wmesa2, Wmesa1>Wmesa2 is satisfied.

Abstract: A voltage nonlinear resistor is made of a sintered body that mainly includes zinc oxide grains, spinel grains including zinc and antimony as main ingredients, and a bismuth oxide phase, in which the bismuth oxide phase includes at least one of alkali metals selected from the group of potassium and sodium at a ratio in the range of 0.036 at % or higher and 0.176 at % or lower. The voltage nonlinear resistor has good voltage nonlinearity and loading service life characteristics, and can be used for a lightning arrester.

Abstract: An optical signal control device includes an optical signal control unit and a drive circuit. The optical signal control unit includes m number of optical waveguides for propagating carrier light and (m×n) number of interaction regions, n number of interaction regions formed on each of the optical waveguides. The drive circuit includes (m×n) number of phase control units. The (m×n) number of phase control unit output a data signal for controlling the action of the (m×n) number of interaction regions to each of the (m×n) number of interaction regions. Each of the (m×n) number of phase control units outputs the data signal so that timing when the carrier light propagates to the interaction region to output the data signal and timing when the data signal arrives at the interaction region are synchronized. One of m and n is two or more.

Abstract: An isolation portion (P) of an insulator (10) of a spark plug (100) electrically insulatively isolates a front end portion (22) of a center electrode (20) and a holding portion (56) of a metallic shell (50) from each other and has an intermediate portion (P2) which extends while its outside diameter varies, thereby ensuring an insulation distance between the two portions. The ratio (S/V) of the surface area (S) of the outer surface (14) of the isolation portion (P) to the volume (V) of the isolation portion (P) satisfies the relation 1.26 mm?1?S/V, whereby the insulation distance between the front end portion (22) and the holding portion (56) is sufficiently ensured while existing dimensional conditions are held unchanged. Through satisfaction of the relation S/V?1.

Abstract: The present invention provides a spark plug that includes a center electrode extending in an axial direction, a ceramic insulator having an axial hole formed in the axial direction to retain the center electrode in a front side of the axial hole and thereby form an assembly unit of the center electrode and the ceramic insulator, a metal shell surrounding an outer circumference of the ceramic insulator to retain therein the assembly unit, and a ground electrode having one end portion joined to a front end face of the metal shell and the other end portion facing the center electrode to define a spark gap therebetween, wherein the spark plug satisfies the following conditions: H?1 mm, Vc?17 mm3 and Ra?1.

Abstract: A spark plug includes a ceramic insulator extending in the direction of an axis (CL1) and a metallic shell provided around the ceramic insulator. Talc is pressed charged between the ceramic insulator and the metallic shell and a crimp portion is formed for fixing the metallic shell and the ceramic insulator while the metallic shell having the ceramic insulator inserted thereinto is supported by a tubular receiving member. The receiving member is made movable in relation to a pressing jig in its radial direction. Thus, at the time of pressing of the talc, etc., the eccentricity between the center axis (CL2), (CL3) of the pressing jig and the axis (CL1) in the radial direction can be reduced, whereby the misalignment between the axis (CL1) and the center axis of the metallic shell or the like assembly error can be suppressed.

Abstract: Provided are a semiconductor optical modulator and a semiconductor Mach-Zehnder optical modulator of high efficiency and high reliability.

Abstract: A ground electrode and a metal shell are joined by welding or the like while an entire end face of a base of the ground electrode is brought into contact with a front end constituent face of the metal shell. The ground electrode has an extending portion extending forward in an axial (O) direction of the ground electrode. A front end portion faces a noble metal tip joined to a front end portion of the center electrode through a bending portion and forms a spark discharge gap (G) therebetween. A gap (a clearance) having a sufficient space to accommodate a virtual sphere (Q) with a radius of 1.2 mm is provided so that the virtual sphere (Q) being in contact with an inner face of the bending portion of the ground electrode is neither in contact with a center electrode nor an insulator.

Abstract: The present invention provides a spark plug which is capable of suppressing a occurrence of crack and separation by determining a structural configuration of a melting portion formed in a junction portion between a discharge portion and a pedestal portion which form an ignition portion that protrudes from a ground electrode. In a profile line shape of a cross section including a center axis P of an ignition portion 80, an exposure surface 88 of a melting portion 83 connects a side surface 82 of a discharge portion 81 and a side surface 85 of a pedestal portion 84. Further, an exterior angle ? formed between an imaginary line Q, which passes through a boundary position X1 between the melting portion 83 and the pedestal portion 84 and a boundary position X2 between the melting portion 83 and the discharge portion 81, and the center axis P at a node C, satisfies 135°???175°.

Abstract: A spark plug includes a ceramic insulator having a tapered rear end stepped portion whose diameter decreases from front to rear and a metal shell having a crimp portion which crimps the rear end stepped portion from the rear end. An area defined by an outer edge of the rear end stepped portion and an inner edge of the crimp portion is 5-25 mm2 when the spark plug is projected on a plane perpendicular to an axial line. An angle formed by a tapered surface of the rear end stepped portion and a plane perpendicular to the axial line is 20-60 degrees. A distance along the axial line from a front end of a proximal portion of the crimp portion to a frontmost position of a contact portion between an inner surface of the crimp and the rear end stepped portion is 0.4-1.8 mm.

Abstract: An optical joint (1) includes a 2×2 MMI coupler (30) and a 2×2 MMI coupler (31) joined to the 2×2 MMI coupler (30). The 2×2 MMI coupler (30) includes a port (32) and a port (33) at one side. The 2×2 MMI coupler (31) includes a port (34) and a port (35) at one side. A light-absorbing region (20) is connected to the port (33), and a light-absorbing region (second light-absorbing section) (21) is connected to the port (34). A reflecting boundary (22) that reflects light propagated through the 2×2 MMI coupler (30) or the 2×2 MMI coupler (31) is formed at the junction portion between the 2×2 MMI coupler (30) and the 2×2 MMI coupler (31).

Abstract: There are provided a spark plug in which a plating film applied to a ground electrode can be relatively easily removed, without cost increase, to prevent deterioration in ignition performance, and a process for producing the spark plug. A spark plug 1 has a metal shell 3, a ground electrode 27 made of a Ni alloy and a Ni plating layer 28 containing Ni as a main component and applied to surfaces of at least a rear end portion of the ground electrode 27 and of the metal shell 3. A Ni plating film 41 applied to a center-electrode-side part of a portion of the ground electrode 27 to be bent has been irradiated with a laser beam or the like, thereby forming a molten layer 29 in which metal materials of the Ni plating film 41 and the ground electrode 27 are molten together on the center-electrode-side part of the portion of the ground electrode 27 to be bent. The Ni plating layer 28 is formed on a part of the ground electrode 27 other than the part irradiated with the laser beam.

Abstract: A vehicle 1 has a torque coupling 8, which is located in a driving power transmission system for transmitting the torque of an engine 2 to front and rear wheels 13f, 13r. The torque coupling 8 changes the torque distribution by adjusting the frictional engaging force of an electromagnetic clutch 16. The vehicle 1 also has a 4WD ECU 21 (CPU), which controls the operation of the torque coupling 8 based on the driving state. The 4WD ECU 21 (CPU) estimates a transfer case oil temperature Tptu. When the transfer case oil temperature Tptu is higher than or equal to a first predetermined transfer case oil temperature KTptu1, the 4WD ECU 21 executes overheat prevention control.

Abstract: A method for manufacturing a spark plug is a method for manufacturing the spark plug having an electrode base member and a noble metal tip welded thereto by means of a laser or an electrode base member, a tip base member joined thereto, and a noble metal tip welded to the tip bases material by means of a laser, and the method includes a laser welding process of welding the electrode base member or the tip base member to the noble metal tip by means of a laser and through use of a laser beam whose BBP value assumes 25 mm·mrad (a radius·a half angle) or less at a time point when a laser beam enters a transfer optical system for guiding the laser beam to areas to be welded where laser welding is to be performed.

Abstract: A spark plug which provides reliable prevention of adhesion and accumulation of carbon on an insulator, includes a center electrode extending in the direction of an axis CL1, a ceramic insulator having an axial hole which extends in the direction of the axis CL1 and in which the center electrode is provided, a cylindrical metallic shell provided externally of the outer circumference of the insulator and having a support portion formed on the inner circumferential surface thereof, and a ground electrode extending from a front end portion of the metallic shell. The insulator has a stepped portion supported by the support portion of the metallic shell, and a leg portion formed forward of the stepped portion. A space SP formed between the leg portion of the insulator and the inner circumferential surface of the metallic shell has a volume of 100 mm3 to 300 mm3 inclusive.

Abstract: A method for manufacturing an ignition plug is provided. The method includes: preparing an insulator having a cavity provided at a leading end portion thereof by disposing a leading end of a center electrode more inwards in an axial hole than a leading end of the insulator; building the insulator in an interior of a metal shell; disposing a ground electrode at a leading end portion of the metal shell; positioning a center of a through hole of the ground electrode and a center of the cavity of the insulator; and welding the ground electrode and the metal shell together after the positioning step.

Abstract: Provided are a spark plug in which the occurrence of spark blowout or the like is restrained for improvement of ignition performance, and a method of manufacturing the spark plug. A ground electrode (27 ) of the spark plug has a protrusion (28 ) which faces a center electrode (5). The distal end surface of the protrusion (28) has a noble metal tip (32) provided at the center thereof and includes an annular fusion portion (33) adjacent to the periphery of the noble metal tip (32), and an annular electrode base metal surface located externally of the annular fusion portion (33). A spark discharge gap (35) is formed between the center electrode (5) and the distal end of the protrusion (28) including the noble metal tip (32).

Abstract: A first exemplary aspect of the present invention is a wavelength-tunable optical transmitter including: a semiconductor substrate (101); a wavelength-tunable light source that is formed on the semiconductor substrate (101) and includes at least a first reflector (102) of a wavelength-tunable type and a gain region (104); a semiconductor optical modulator formed on the semiconductor substrate (101); a first semiconductor optical waveguide (105c) that is formed on the semiconductor substrate (101) and smoothly connected to the wavelength-tunable light source; a second semiconductor optical waveguide (105d) that is formed on the semiconductor substrate and smoothly connected to the semiconductor optical modulator; a waveguide coupling region (108) in which the first and second semiconductor optical waveguides are collinearly coupled with a length LC that is not equal to m/2 (m: integer) times a complete coupling length LC0; and a second reflector (113) formed at an end of the waveguide coupling region (108).

Abstract: A spark plug with excellent vibration resistance performance and resistor load life-span characteristics, and a reduced diameter which is achieved by strengthening adhesion between a resistor and a conductive glass sealing layer.

Abstract: Provided is a traveling-wave type semiconductor optical phase modulator capable of high speed and low voltage operation by improving an n-SI-i-n-type layered structure. A first exemplary aspect of the present invention is a waveguide-type semiconductor optical modulator including: a semiconductor substrate (101); a first n-type cladding layer (103) and a second n-type cladding layer (108) formed on the semiconductor substrate (101); an undoped optical waveguide core layer (104) and an electron trapping layer (107) formed between the first n-type cladding layer (103) and the second n-type cladding layer (108); and a hole supplying layer (106) formed between the undoped optical waveguide core layer (104) and the electron trapping layer (107).