Nippon Telegraph and Telephone Public Corporation

Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Other

Honda Tsushin Kogyo Co., Ltd.

Fumiaki Hanawa

Motohiro Nakahara

Yasuyuki Inoue

Koichi Arishima

Shoichi Suto

Kenji Yokoyama

Hiroshi Takahashi

Ryo Nagase

Yasufumi Yamada

Motohaya Ishii

Katsunari Okamoto

Masao Kawachi

Akira Miyashita

Takao Edahiro

Nobuo Tomita

Masayuki Okuno

Kuniharu Kato

Shin Sumida

Akimasa Kaneko

Hisashi Izumita

Nobuo Inagaki

Senichi Suzuki

Takao Kimura

Norio Takato

Fumihiro Ebisawa

Yoshitaka Enomoto

Kuninori Hattori

Tatsuo Izawa

Hiroyuki Suda

Takashi Yoshida

Toshiaki Eguchi

Yuichi Kikuchi

Hiroaki Yamada

Tadashi Miyashita

Naohide Goto

Satoru Konno

Toru Maruno

Yoshi Kurosawa

Jyunko Katoh

Tetsuo Yoshizawa

An optical connector plug to be inserted to an adapter, is arranged such that a pair of engaging parts for expanding an elastic locking piece provided on a side of the adapter by a taper part and locking it with a step part is provided on a tip part of a plug frame which is a body of the plug; a locking releasing piece movable along an insertion-extraction direction is provided between the pair of engaging parts; a taper part for releasing a locking action of the elastic locking piece when extracting the plug is provided at a rear end of the locking releasing piece; and the taper part of the engaging parts has such a shape that the connecting stress is not lowered before being locked when inserting the plug.

Optical connector plug

An optical element module is equipped with a casing, an optical element provided inside the casing, a pipe which communicates the inside of the casing to the outside, and a primary coated optical fiber which is inserted through the pipe and connected to the optical element.

Optical element module with a primary coated optical fiber

In a light waveguide circuit including a plurality of waveguides having different length, a material (,) having a temperature coefficient of a refractive index including a symbol different from that of a temperature coefficient of an effective refractive index of the waveguide (,) is charged into a groove (,) formed by removing the upper clad and the core from the waveguide (,), or a groove (,) formed by removing the upper clad, the core and the lower clad from the waveguide (,). A difference in length of the removed portions between adjacent waveguides is proportional to a difference in length of the waveguides which were not removed and remained.

Optical waveguide circuit, its manufacturing method and optical waveguide module having the optical waveguide circuit

A guided-wave circuit module includes a guided-wave circuit chip having an input waveguide part and an output waveguide part at the ends thereof, a guided-wave circuit part having a predetermined function and positioned between the input waveguide part and the output waveguide part; and a holder for supporting the guided-wave circuit chip, wherein the guided-wave circuit part of the guided-wave circuit chip does not come in contact with the chip holder; at least part of the input and output waveguide parts of the guided-wave circuit chip is fixed to the holder with a fixing agent; and the packaged chip does not have a warp which leads to deterioration of characteristics. A fixing agent having a high hardness is applied to the periphery of the endfaces of the input and output waveguide parts of the guided-wave circuit module and to the periphery of the fiber endfaces of the optical fiber array connected to the module. Therefore, these endfaces can accurately be polished and the waveguide can be connected to the optical fibers at a sufficiently low fiber connection loss and a high return loss.

Guided-wave circuit module and wave-guiding optical component equipped

Manufacturing method of doped silica glass suitable for optical fiber wherein quartz powder or SiO.sub.2 glass fine particles are exposed to a gas for producing the doped silica glass containing SiCl.sub.4, a gaseous additive and water vapor (H.sub.2 O) to add the dopant to the glass body, and then the resulting glass body is fused at a high temperature, thereby producing a transparent doped silica glass in which the production of the glass particles, the addition of the dopant, and the vitrification of the glass body are carried out by separate steps under respective suitable conditions. The manufacturing speed is remarkably increased because of the separate steps. The content of the dopant is not limited, but can be adjusted with any desired amount by changing the reaction time of dissolution. Dopant components like PbO.sub.2, SnO.sub.2, ZnO which were typically not added to the glass body can now be added thereto. Also, a method of manufacturing an optical fiber preform is disclosed wherein the doped silica glass is deposited and fused on a starting material which is inclined by an angle within a range of 5.degree.-90.degree. with respect to a blow-off direction of the flow of the doped silica glass to form a transparent doped silica glass body having a uniform outer diameter and a uniform boundary surface at a high synthesizing speed. This latter method aids mass production of optical fibers at low cost.

Fabrication methods of doped silica glass and optical fiber preform by

A method of fabricating an optical fiber preform wherein a synthesizing torch is inclined between 10.degree. and 60.degree. with respect to the rotation axis of a seed rod. Moving the rod while rotating it, a glass raw material gas and a flame forming gas are blown out individually from the torch to synthesize glass particles which are deposited onto one end of the rod, so that a cylindrical porous preform is grown in the direction of the rotation axis of the rod. Then the porous preform is heated at a high temperature to vitrify the porous preform into a transparent optical fiber preform. At least one exhaust port is disposed at a distance of 1 mm to 50 mm from the periphery of the porous preform and in the vicinity of the growing surface of the porous preform. In fabricating the porous preform the outer diameter fluctuations are small, and the preform is formed stably without formation of cracking on the periphery of the preform.

Method of fabricating multi-mode optical fiber preforms

A refractory starting member is rotated and, at the same time, moved along the axis of rotation. A glass raw material for the formation of the core of a porous preform and consequently an optical fiber preform is introduced into a high temperature portion near the tip of a high temperature burner from a nozzle for the core disposed in alignment with the center of rotation of one end face of the starting member. The glass raw material blown out from the nozzle for the core are caused by the flames of the high temperature burner to react to produce glass fine particles, which are deposited on abovesaid end face of the starting member at the central portion thereof in its axial direction to form a porous core. At least one nozzle for spraying a glass raw material for the formation of the cladding of the optical fiber preform is disposed opposite to the end face of the starting member but a little deviated from the axis of rotation thereof, or disposed opposite to the peripheral surface of the porous core. The glass raw material for the cladding is sprayed from the nozzle for the cladding to the high temperature portion of the high temperature burner, and caused to react to form glass fine particles, which are deposited on the end face of the starting member on the outside of the porous core or on the peripheral surface thereof at the same time as the formation of the latter, forming a porous cladding. The porous preform thus obtained is moved into a high temperature furnace provided on the path of movement of the preform for the vitrification thereof into an optical fiber preform.

Continuous optical fiber preform fabrication method

Growing community of inventors

Yokohama, Japan

Fumiaki Hanawa