Abstract: 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 ?m. The arrangement pattern of individual unit components includes nine conductor disks so as to correspond to a 3×3 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.

Abstract: 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 ?m. The arrangement pattern of individual unit components includes nine conductor disks so as to correspond to a 3×3 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.

Abstract: The present embodiment relates to an optical device or the like that is high in non-linearity and resistance to UV light and includes a structure allowing stable wavelength conversion. The optical device is comprised of glass containing SiO2 and comprises a repetitive structure including first sections being crystallized regions in which a radial polarization-ordered structure is formed and second sections being non-crystallized regions alternately arranged along a center axis extending from a center of a light-incidence end face toward a center of a light-emission end face.

Abstract: 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×n optical fibers in the first optical fiber group are housed in any of the plurality of first connectors, and the m×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.

Abstract: 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×n optical fibers in the first optical fiber group are housed in any of the plurality of first connectors, and the m×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.

Abstract: 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×n optical fibers in the first optical fiber group are housed in any of the plurality of first connectors, and the m×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.

Abstract: An optical cross-connect component is disclosed. The optical cross-connect component includes an optical fiber group having m×n optical fibers, one ends and the other ends of the m×n optical fibers being arranged in a matrix of m rows×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×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×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.

Abstract: An optical cross-connect component is disclosed. The optical cross-connect component includes an optical fiber group having m×n optical fibers, one ends and the other ends of the m×n optical fibers being arranged in a matrix of m rows×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×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×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.

Abstract: 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×n optical fibers in the first optical fiber group are housed in any of the plurality of first connectors, and the m×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.

Abstract: In a wavelength selective switch, respective values are set to satisfy an expression (?2>2×?1+?). Therefore, when an inclination angle of a mirror is changed to move primary reflected light to be close to an output port in operation, secondary reflected light moves away from the output port. Therefore, when an inclination angle of a mirror is changed to couple the primary reflected light to the output port, coupling of the secondary reflected light to the output port is suppressed.

Abstract: An optical fiber connecting method and optical fiber connecting structure which can efficiently connect a multicore fiber to a plurality of single-core fibers with high accuracy. The method comprises preparing an MT ferrule for holding an MCF, axially rotating and positioning the MCF with respect to the MT ferrule, and then fixing the MCF to the MT ferrule; preparing an MT ferrule for holding a plurality of SCFs, positioning them such that cores are arranged at respective positions corresponding to arrangements of a plurality of cores in the MCF, and then fixing the plurality of SCFs to the MT ferrule; and positioning and joining the MT ferrules such that the plurality of cores face the respective single cores, so as to connect the MCF to the plurality of SCFs.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Bidirectional optical communication system transmits optical signals with two different wavelengths .lambda..sub.1 and .lambda..sub.2 (.lambda..sub.1 <.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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 &mgr;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 &mgr;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/nm2 and not more than −0.1 ps/km/nm2; transmission loss not more than 0.5 dB/km; polarization mode dispersion not more than 0.7 ps.km−½; mode field diameter not less than 4.5 &mgr;m and not more than 6.5 &mgr;m; cut-off wavelength not less than 0.7 &mgr;m and not more than 1.7 &mgr;m in the length of 2 m; and bending loss at the diameter of 20 mm, not more than 100 dB/m.