Abstract: A ferrule includes a main body including inner and outer walls and a connection end surface at which a tip of an optical fiber is to be disposed. The inner wall has fiber holes. The ferrule includes an adhesive filling part disposed in the main body on an opposite side from the connection end surface with respect to the inner wall, an upper opening that opens from the outer wall to the adhesive filling part, and a lower opening that opens from the outer wall to the adhesive filling part and is disposed on an opposite side from the upper opening. The inner wall has a first surface and a second surface protruding toward the adhesive filling part from the first surface. The upper opening is opened in a location along the first surface. The lower opening is opened in a location along the second surface.

Abstract: A high frequency variable attenuation circuit includes an input terminal, an output terminal, a first resistor, a second resistor, a third resistor, and a first switching circuit. The first switching circuit has an output side resistor and an output side switching element that are connected in series to each other. The first switching circuit has a first circuit end connected to the second end of the second resistor and the output terminal, and a second circuit end connected to the ground.

Abstract: An aspect of the present invention simplifies a method of manufacturing a mode converter. A mode converter (10) includes: a post-wall waveguide (PW); a microstrip line (MS); and a blind via (BV) configured to carry out conversion between a waveguide mode of the post-wall waveguide (PW) and a waveguide mode of the microstrip line (MS), the blind via (BV) having a shape approximated by a shape obtained by combining a plurality of cylinders (C1 to C4), each of the plurality of cylinders (C1 to C4) having a diameter equal to the diameter of through vias 14i.

Abstract: An attachment cleaning tool includes: a cleaning tool; and an attachment detachably attached to the cleaning tool. The cleaning tool includes: cleaning bodies that clean connection end surfaces of ferrules of an optical connector; head members each that press the cleaning bodies against the connection end surfaces; nozzle members that respectively accommodate the head members; a feeding mechanism that supplies and withdraws the cleaning bodies with respect to the head members; and an accommodating body which accommodates the feeding mechanism. Each of the connection members of the attachment includes: an attachment portion attached to a tip portion of each of the nozzle members; and a tubular portion that protrudes from the attachment portion in a longitudinal direction of the nozzle members and into which one of the ferrules is inserted. The connection members move following a relative movement of the nozzle members in the lateral direction.

Abstract: An aspect of the present invention is to reduce return loss in a mode converter. A mode converter (10) includes an excitation pin (through via TV) configured to carry out mutual conversion between a waveguide mode of a post-wall waveguide (PW) and a waveguide mode of a microstrip line (MS). The mode conductor includes a pair of wide walls (conductor layers 12 and 13), in which first and second anti-pads (anti-pads 12c, 13c) are formed, respectively. The first and second anti-pads each have an inner edge including the excitation pin and each have an outer size (diameter D12) that is more than 5 times and less than 6 times as large as the diameter (DT) of the excitation pin.

Abstract: An optical fiber cable includes: optical fibers each including a glass portion including a core and a cladding surrounding the core, a primary covering layer covering the cladding, and a secondary covering layer covering the primary covering layer; and a sheath accommodating the optical fibers in an internal space. A value of a micro-bend loss characteristic factor F?BL_GO is 5.

Abstract: A variable gain amplifier includes a differential amplifier circuit having a pair of input terminals and a pair of output terminals, and a first variable attenuation circuit connected between at least one of the pair of input terminals and the pair of output terminals of the differential amplifier circuit and capable of switching a resistance value on the basis of a control signal which is input from the outside.

Abstract: An optical fiber cable includes: optical fibers each including a glass portion including a core and a cladding surrounding the core, a primary covering layer covering the cladding, and a secondary covering layer covering the primary covering layer; and a sheath accommodating the optical fibers in an internal space. A value of a micro-bend loss characteristic factor F?BL_G?? is 1.2×10?9 or less when represented by F?BL_G??=F?BL_G×F?BL_??×Dc.

Abstract: A wiring board includes a first substrate, a second substrate composed of a material different from a material of the first substrate, a wiring supported by the first substrate, and a terminal supported by the second substrate and connected to the wiring. The first and second substrates are disposed on a same side with respect to the wiring. In a plan view, the first substrate overlaps the wiring but not the terminal. In the plan view, the second substrate overlaps the terminal.

Abstract: An oxide superconducting wire includes: a substrate having a main surface; a superconducting layer disposed above the substrate and formed of a rare-earth high-temperature superconductor; and a protective layer disposed on the superconducting layer and in contact with the superconducting layer. An a-axis direction is oriented perpendicular to the main surface of the substrate. The superconducting layer includes a-axis oriented grains oriented along the a-axis direction. An a-axis oriented grain ratio is defined as a proportion of the a-axis oriented grains to an entirety of crystal grains forming the superconducting layer. The a-axis oriented grain ratio is greater than or equal to 4.1% and less than or equal to 11.9%.

Abstract: A non-contact direction changer includes: a guide groove that guides an optical fiber and changes a direction of advancement of the optical fiber from a first direction to a second direction; a bottom ejection opening at a bottom of the guide groove; and one or more side ejection openings on at least one of opposite side surfaces of the guide groove. A fluid is ejected into the guide groove through the bottom ejection opening. A fluid is ejected into the guide groove through the one or more side ejection openings.

Abstract: An optical fiber cable production method includes: feeding a core including optical fibers; winding a reinforcing wrap around the core and forming an overlapping portion in which end portions of the reinforcing wrap overlap each other at a portion of the reinforcing wrap in a circumferential direction; and performing extrusion molding of a sheath on an outside of the reinforcing wrap. The overlapping portion extends in a longitudinal direction of the optical fibers. In the performing extrusion molding, a resin that forms the sheath is inserted into a portion of the overlapping portion.

Abstract: A filter device includes: an optical fiber that allows light having a predetermined wavelength to propagate in multimode; a first higher-order mode filter that removes at least part of the light in any higher order mode than a predetermined mode in the light in the multimode propagating in the optical fiber; and a fiber Bragg grating that transmits the light having the predetermined wavelength and reflects light having a particular wavelength longer than the predetermined wavelength.

Abstract: An optical fiber preform production method includes: inserting at least one glass rod into at least one through-hole that penetrates a cladding glass body that is a cladding of an optical fiber; integrating a dummy rod by either integrating a solid dummy silica rod with a first end of the cladding glass body by heating the first end to close a first opening of the through-hole that opens in the first end, or forming a base end seal that closes the first opening in the first end and integrating the solid dummy silica rod with the base end; and closing a second opening of the through-hole that opens in a second end of the cladding glass body by heating and deforming the second end.

Abstract: A plug connector mounted on a board and that mates with a receptacle connector includes at least three signal contacts and two power contacts each including a contact portion that contacts the receptacle connector and a block that holds the signal contacts and the power contacts. The block includes a body and a fitting portion that protrudes away from the body and is inserted into a fitting port of the receptacle connector, and the signal contacts and the power contacts are disposed alternately in a row along an arrangement direction and symmetrically about a line that passes through a center position of the plug connector and is orthogonal to the arrangement direction when viewed from a fitting direction to the receptacle connector.

Abstract: An optical transceiver includes a case including a heat sink, one or more heat generating bodies disposed in the case, one or more heat conducting portions protruding from an inner wall surface of the case and thermally contacting the one or more heat generating bodies, and a heat pipe that transfers heat from the one or more heat conducting portions to the heat sink.

Abstract: A ferrule, for an optical connector, includes: a main body part formed with a fiber hole configured to accommodate insertion of an optical fiber. The main body part is formed of a material having a coefficient of linear expansion within a range of 1.7×10?5 to 3.0×10?5. A ratio of an inner diameter dh of the fiber hole to an outer diameter df of a cladding of the optical fiber is within a range of 99.632 [%]?dh/df?99.880 [%].

Abstract: A multi-core optical fiber preform includes: a rod-shaped main cladding body having one or more main inner holes; main core rods inserted into the one or more main inner holes; and a tip continuously-installed portion disposed at one end of the rod-shaped main cladding body and including a glass rod having no core rod or having one core rod.

Abstract: A light diffraction element unit includes an optically-transparent substrate; a light diffraction element disposed on a main surface of the optically-transparent substrate; and a three-dimensional alignment mark disposed on the main surface in a vicinity of the light diffraction element and having a thickness greater than a thickness of the light diffraction element.

Abstract: An optical fiber fixing tool includes: a fiber accommodating body having a fiber accommodating groove that accommodates: at least a part of an uncovered bare portion of an optical fiber and a boundary part between the uncovered bare portion and a covered portion of the optical fiber, a cover being removed to expose a bare fiber in the uncovered bare portion; and a fixing resin that fills an inside of the fiber accommodating groove and fixes at least the part of the uncovered bare portion and the boundary part. In a cross-sectional view of the fiber accommodating groove viewed from a cross section of the optical fiber, the entire uncovered bare portion and the entire boundary part are accommodated in the fiber accommodating groove, and the fixing resin covers an entire outer circumference of the uncovered bare portion and an entire outer circumference of the boundary part.