Sumitomo Electric Industries, Limited

Nippon Telegraph and Telephone Corporation

Nippon Telegraph and Telephone Public Corporation

Osaka University

Tokyo Nippon Telegraph Public Corporation

Hiroo Kanamori

Tomonori Kashiwada

Masayuki Nishimura

Masashi Onishi

Yasushi Koyano

Shinji Ishikawa

Gotaro Tanaka

Hiroshi Yokota

Michihisa Kyoto

Akira Urano

Haruhiko Aikawa

Yoichi Ishiguro

Minoru Watanabe

Hiroshi Suganuma

Yuichi Ohga

Masumi Ito

Sumio Hoshino

Futoshi Mizutani

Ichiro Tsuchiya

Koji Nakazato

Masahide Saito

Naoki Yoshioka

Chisai Hirose

Yoshiaki Miyajima

Eisuke Sasaoka

Tomomi Sano

Toshio Danzuka

Chie Fukuda

Masahiro Takagi

Masahide Saitoh

Yuji Matsuura

Masakazu Shigehara

Masayuki Shigematsu

Masataka Nakazawa

Takashi Kogo

Chizai Hirose

Yoshiki Kuhara

Shigeru Tanaka

Motoki Kakui

Toshiaki Kakii

Yasushi Fujimura

Yasuhiro Iguchi

Naoyuki Yamabayashi

Takeshi Inoue

Motohiro Nakahara

Takafumi Ohtsuka

Tatsuhiko Saito

Shigeru Semura

Nobuo Inagaki

Shigeru Hirai

Dai Yui

Ichiro Yoshimura

Shigeru Tomita

Izumi Sankawa

Koji Amemiya

Kazunori Chida

Manzo Yamaguchi

Hikaru Satoh

Hisasi Izumita

Masahi Onishi

Horoshi Yokota

Tomonori Kashiwara

Kazunari Kimino

Junichi Takahara

A radiation device or the like has a structure for selectively converting thermal energy into an electromagnetic wave. The radiation device has a conductor layer, a semiconductor layer, and a plurality of conductor disks. The plurality of conductor disks are arranged on the semiconductor layer so that the same arrangement pattern is constituted in each of a plurality of unit constituent regions each having a rectangular shape with a side of 4.5 to 5.5 &#x3bc;m. The arrangement pattern of individual unit components includes nine conductor disks so as to correspond to a 3&#xd7;3 matrix, and the nine conductor disks include four or more kinds of conductor disks having diameters different from each other. As a result, a two-dimensional periodic structure of the arrangement pattern is formed on the semiconductor layer.

Radiation device and emission cooling device

An optical cross-connect component mutually connecting an end of a first optical fiber group and an end of a second optical fiber group is disclosed. The optical cross-connect component includes a plurality of first connectors housing therein the end of the first optical fiber group, and a plurality of second connectors housing therein the end of the second optical fiber group. The m&#xd7;n optical fibers in the first optical fiber group are housed in any of the plurality of first connectors, and the m&#xd7;n optical fibers in the second optical fiber group are housed in any of the plurality of second connectors. The end of the first optical fiber group and the end of the second optical fiber group are connected so as to be butted to each other.

Optical cross-connect component

An optical cross-connect component is disclosed. The optical cross-connect component includes an optical fiber group having m&#xd7;n optical fibers, one ends and the other ends of the m&#xd7;n optical fibers being arranged in a matrix of m rows&#xd7;n columns, a plurality of first connectors housing the one ends of the optical fiber group, and a plurality of second connectors housing the other ends of the optical fiber group. The m&#xd7;n optical fibers are housed in any of the plurality of first connectors, and one first connector collectively houses therein n optical fibers arranged in at least any one row of the m rows. The m&#xd7;n optical fibers are housed in any of the plurality of second connectors, and one second connector collectively houses therein m optical fibers arranged in at least any one column of the n columns.

The present invention relates to a branch line monitoring system and branch line monitoring method comprising a configuration which improves the S/N ratio of measurement information and can be realized inexpensively. This system is provided with optical filters which correspond to optical fiber lines to be monitored as branch lines. These optical filters each have such a cutoff characteristic as to cut of f respective one channel of monitor light but transmit therethrough the remaining monitor light and signal light. When the optical filters having such a cutoff characteristic are provided, each of the optical fiber lines is monitored by use of a plurality of channels of monitor light other than the one cut off by the optical filter provided so as to correspond thereto. Consequently, as compared with the case where one optical fiber line is monitored by its corresponding one channel of monitor light, the S/N ratio of measurement information is improved, whereby highly accurate monitoring is possible.

Branch line monitoring system and branch line monitoring method

The present invention relates to an optical I/O module and light-reflecting device comprising a structure excellent in expandability having a high degree of freedom in designing. The optical I/O module according to the present invention comprises a directional coupler having, at least, input and output ports for constituting a part of a transmission line and an intermediate port for constituting a branch; and a light-reflecting device, optically connected to the intermediate port, for transmitting therethrough a specific wavelength. This structure can realize various configurations which allow a specific wavelength to be dropped from the transmission line and to be added to the transmission line, without influencing the configuration of the transmission line.

Optical input/output module and light-reflecting device

The present invention relates to a dispersion compensating fiber for improving a transmission system with it in total chromatic dispersion and dispersion slope in the 1.55 .mu.m wavelength band. The dispersion compensating fiber according to the present invention is characterized by having the following characteristics for light in the 1.55 .mu.m wavelength band: chromatic dispersion not less than -40 ps/km/nm and not more than 0 ps/km/nm; dispersion slope not less than -0.5 ps/km/nm.sup.2 and not more than -0.1 ps/km/nm.sup.2 ; transmission loss not more than 0.5 dB/km; polarization mode dispersion not more than 0.7 ps.multidot.km.sup.-1/2 ; mode field diameter not less than 4.5 .mu.m and not more than 6.5 .mu.m; cut-off wavelength not less than 0.7 .mu.m and not more than 1.7 .mu.m in the length of 2 m; and bending loss at the diameter of 20 mm, not more than 100 dB/m. The dispersion compensating fiber is optically connected with a dispersion shifted fiber as a compensated object at a ratio of appropriate lengths, which can improve the system including the dispersion compensating fiber in the total chromatic dispersion and dispersion slope of the system in the 1.55 .mu.m band.

Dispersion compensating fiber and optical transmission system including

Bidirectional optical communication system transmits optical signals with two different wavelengths .lambda..sub.1 and .lambda..sub.2 (.lambda..sub.1 &lt;.lambda..sub.2) between a broadcasting station and a plurality of ONU terminals. Bisecting separation of .lambda..sub.1 and .lambda..sub.2 requires expensive WDMs. .lambda..sub.1 -selective photodiode which absorbs all the .lambda..sub.1 light and allows all the .lambda..sub.2 to pass through is proposed. The energy gap Eg.sub.1 of the light receiving layer is determined to be smaller than hc/.lambda..sub.2 and larger than hc/.lambda..sub.1. The .lambda..sub.1 -selective photodiode and the other photodiode are positioned in series on a beam line, which dispenses with WDMs.

PD/LD module and PD module

A process for producing fluoride glass, including the steps of: introducing a raw material for fluoride glass into a heating vessel; and heating the raw material in the heating vessel, while causing the heating vessel to have a negative internal pressure and introducing an inert gas into the heating vessel, thereby to melt the raw material under heating.

Process of producing fluoride glass

A dispersion compensating fiber has a negative chromatic dispersion slope and a value of chromatic dispersion suitable for practical application, and a bending loss thereof with a bending diameter of 40 mm is smaller than 0.01 dB/m at 1.55 .mu.m. A diameter of a core is larger than 3 .mu.m but smaller than 4 .mu.m. A ratio (Da/Db) of the diameter of the core to an outer diameter of a first cladding is between 0.4 and 0.6 both inclusive. A relative refractive index difference of the core to a second cladding, (nc-n2)/n2, is larger than 0.02 but smaller than 0.03. A relative refractive index difference of the first cladding to the second cladding, (n2-n1)/n2, is larger than 0.004 but smaller than 0.01. This dispersion compensating optical fiber has a sufficient negative chromatic dispersion slope at wavelengths (1.55 .mu.m to 1.65 .mu.m both inclusive) around 1.55 .mu.m and a bending loss thereof at the wavelength of 1.55 .mu.m with the bending diameter of 40 mm is smaller than 0.01 dB/m.

Optical transmission system with dispersion compensating optical fiber

This invention relates to a dispersion-compensating fiber which can be drawn at a lower temperature and can further reduce optical transmission loss. This dispersion-compensating fiber comprises a core portion containing a high concentration of GeO.sub.2 and a cladding portion formed around the outer periphery of the core portion. The cladding portion comprises a first cladding containing fluorine or the like as an index reducer, a second cladding having a higher refractive index than that of the first cladding, and a third cladding which becomes a glass region substantially noncontributory to propagation of signal light. In particular, the third cladding contains a desired impurity such that the glass viscosity thereof becomes lower than that of the second cladding or pure silica cladding at a predetermined temperature.

Dispersion-compensating fiber and method of fabricating the same

Lead-containing fluoride glass comprises 50-70 mol % of ZrF.sub.4, 3-5 mol % of LaF.sub.3, 0.1-3 mol % of YF.sub.3, and 2-15 mol % of NaF and/or LiF and/or CsF, where LaF.sub.3 +YF.sub.3 =4.5-6 mol %, and further comprises lead. An optical fiber comprises a core made of the lead-containing fluoride glass and a cladding surrounding the core. A process for producing an optical fiber comprises forming a base material for a core of the lead-containing fluoride glass, forming a base material for a cladding of fluoride glass containing 30-60 mol % of HfF.sub.4, and drawing the base materials into an optical fiber at a drawing temperature of 315-340 .degree. C.

Lead-containing fluoride glass, optical fiber and process for producing

This process for producing an optical waveguide comprises a step of sintering a glass fine-particle layer to form a upper cladding layer, and a step of controlling a refractive index of the upper cladding layer by changing a temperature decreasing rate when the glass layer is cooled down to the room temperature.

Process for producing optical waveguide

The present invention relates to a package in which an optical waveguide module is mounted, at least having such structure as to reduce influence of expansion or contraction (thermal stress) of a metal housing, caused with a temperature change of the external environment and applied on junction parts between an optical waveguide substrate and members for fixedly supporting tip portions of input and output optical fibers. This package comprises a cavity for housing the whole of the optical waveguide module as covered with a buffer protection material, and a metal housing having through holes for leading the above optical fibers to the outside. Particularly, the optical fibers and the through holes are bonded and secured with a filler having higher airtightness than the buffer protection material and having a lower tensile modulus than a metal material forming the housing.

Package with optical waveguide module mounted therein

A method for producing an oxide glass thin film is provided, in which volatilization of additives in a porous film from which the thin film is formed is effectively suppressed, and which the oxide glass film has a desired arrangement of refractive index with a low optical loss. According to this method, glass fine particles mainly containing SiO.sub.2 with a first additive are deposited on a substrate to form a porous thin film. A gas containing a second additive is supplied to a first chamber and heated to a first predetermined temperature profile to provide a heated gas containing an oxide. After disposing the substrate in a second chamber communicated with the first chamber, the substrate is heated to make the deposited porous glass into transparent glass while controlling a temperature in the second chamber according to a second temperature profile. A carrier gas is flowed from the first chamber to the second chamber to transfer the heated gas and oxide from the first chamber to the second chamber during heating. The temperature of the first predetermined temperature profile is maintained higher than the temperature of the second predetermined temperature profile at the same time. In addition, the heated gas contains a component that is also present in the first additive.

Method for producing glass thin film

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Yokohama, Japan

Hiroo Kanamori