Abstract: An optical fiber for Raman amplification amplifies a signal light with a pumping light. A chromatic dispersion at a wavelength of 1,550 nm is in a range between ?70 ps/nm/km and ?30 ps/nm/km. Raman gain efficiency with a pumping light of 1,450 nm is equal to or more than 5 (W×km)?1. Nonlinear coefficient at the wavelength of 1,550 nm is equal to or less than 5.0×10?9 W?1. Zero-dispersion wavelength is neither at a wavelength of the signal light nor at a wavelength of the pumping light. Cut-off wavelength is equal to or less than the wavelength of the pumping light.

Abstract: In the present invention, a charge transfer unit is arranged on a first-plane side of a thinly-formed semiconductor base. Charge accumulating units are arranged on a second-plane side, the opposite side. A depletion prevention layer is arranged closer to the second-plane side than the charge accumulating units. The depletion prevention layer prevents a depletion region around the charge accumulating units from reaching the second plane of the semiconductor base. The depletion prevention layer can suppress surface dark current going into the charge accumulating units. Meanwhile, an energy ray incident from the second-plane side pass through the depletion prevention layer to generate signal charges in the charge accumulating units (depletion regions). The charge accumulating units collect, on a pixel-by-pixel basis, the signal charges which are to be transported to the charge transfer unit under voltage control or the like, and then are read to exterior as image signals.

Abstract: An optical fiber has a Raman gain efficiency with a pump power at 1450 nanometers of equal to or more than 4 m/W, and a ratio of a nonlinear parameter ? at a wavelength of 1550 nanometers to the Raman gain efficiency with a pump power of 1450 nanometers is equal to or less than 3.

Abstract: A mode field diameter of an optical fiber at a wavelength of 1300 nm is equal to or larger than 5.4 ?m. A light of a wavelength of 1250 nm is propagated through the optical fiber in a single mode. A bending loss of the optical fiber with a bending radius of 1 mm at the wavelength of 1300 nm is equal to or lower than 1 dB/turn.

Abstract: Provided is a single-mode optical fiber that propagates an optical signal at a wavelength of 1310 nm, in single-mode operation; has a mode field diameter of 6.6 ?m or more at the wavelength of 1310 nm; and a macro bending loss of at most 0.1 dB/10 turns with a bending radius of 7.5 mm at a wavelength of 1650 nm.

Abstract: An optical fiber for optical amplification, characterized in that a full width at half maximum of gain spectrum is 45 nm or more; and a maximum value of power conversion efficiency is 80% or more. A method for producing a rare earth element-doped glass for use in manufacturing the optical fiber, which comprises a deposition step of depositing fine silica glass particles and a co-dopant (a) to prepare an aggregate of fine silica glass particles doped with the co-dopant (a); and a immersion step of immersing the aggregate of fine silica glass particles prepared in the deposition step in a solution containing the rare earth element and the co-dopant (b) to thereby dope the aggregate of fine silica glass particles with the rare earth element component and the co-dopant (b).

Abstract: This invention relates to an optical fiber for long period grating (LPG), LPG components, and manufacturing method of LPG used as a mode coupler, an optical filter, etc. The optical fiber for LPG comprises a core layer, a first cladding layer that surrounds said core layer and transmits the cladding modes, and a second cladding layer that surrounds said first cladding layer and confines the optical signal of the cladding mode within said first cladding layer. The LPG component comprises an optical fiber for LPG, a coating reinforcement to cover and reinforce said optical fiber for LPG. The manufacturing method of LPG comprises a step of preparation of an optical fiber, a step of constructing the LPG on a predetermined region in said core of said optical fiber by irradiating laser light on said region over a predetermined period corresponding to the LPG, on the predetermined part of said optical fiber, and a step which covers and reinforces said grating region.

Abstract: An optical fiber for Raman amplification amplifies a signal light with a pumping light. A chromatic dispersion at a wavelength of 1,550 nm is in a range between ?70 ps/nm/km and ?30 ps/nm/km. Raman gain efficiency with a pumping light of 1,450 nm is equal to or more than 5 (W×km)?1. Nonlinear coefficient at the wavelength of 1,550 nm is equal to or less than 5.0×10?9 W?1. Zero-dispersion wavelength is neither at a wavelength of the signal light nor at a wavelength of the pumping light. Cut-off wavelength is equal to or less than the wavelength of the pumping light.

Abstract: An optical fiber, which is employed as a transmission line of an optical communication system, has a cable-cutoff wavelength of not longer than 1430 nanometers at the wavelength of 1450 nanometers, a mode-field diameter of not less than 7 micrometers and not more than 9 micrometers, a transmission loss of not more than 0.285 dB/km, and a dispersion of 0.1 to 4 ps/nm/km.

Abstract: The present invention provides an optical fiber having dispersion of ?8 ps/nm/km or less at a wavelength of 1460 nm including a reference layer which is a reference of a refractive index profile and at least three glass layers that exist inside the reference layer, characterized in that when it is assumed that the maximum relative refractive index difference of the first glass layer formed innermost of the at least three glass layers with respect to the reference layer is ?1, the relative refractive index difference of the second glass layer formed second from the inside with respect to the reference layer is ?2, the relative refractive index difference of the third glass layer formed third from the inside with respect to the reference layer is ?3 and the relative refractive index difference of the reference layer with respect to pure quartz glass is ?C, ?1>?3>?2, ?1?1.0% and ?C<0 are satisfied, and further provides an optical-module and a Raman amplifier using the optical fiber.

Abstract: Provided is a single-mode optical fiber that propagates an optical signal at a wavelength of 1310 nm, in single-mode operation; has a mode field diameter of 6.6 ?m or more at the wavelength of 1310 nm; and a macro bending loss of at most 0.1 dB/10 turns with a bending radius of 7.5 mm at a wavelength of 1650 nm.

Abstract: When a lower layer address pair of a transferred lower layer frame is counted a predetermined number of times or more, a packet transfer apparatus (2) sends the lower layer address pair to a frame transfer apparatus (3). The frame transfer apparatus (3) counts the transfer frequency of the lower layer frame having the lower layer address pair.

Abstract: A route control server (1) sends destination information acquired by a router (2) in a managed area and transfer management information corresponding to the destination information to another route control server and determines the output interface of a packet on the basis of the destination information and transfer management information. A packet transfer apparatus (3) executes mutual conversion and transfer of an upper layer packet on a user terminal side and a lower layer frame on an optical wavelength path side. An admission control server (4) sets, of the optical wavelength paths of the photonic network, an optical wavelength path formed from a cut-through optical wavelength path which has a guaranteed band and directly connects packet transfer apparatuses of transmission source and destination in accordance with an optical wavelength path connection request from a transmission source user terminal.

Abstract: An optical fiber includes a core and a cladding which are made from silica glass, allows single mode transmission at a wavelength of 1100 nm, and has a mode field diameter of not less than 4 ?m at a wavelength of 1100 nm, and a bending loss of not more than 1 dB per turn with a curvature radius of 1 mm at a wavelength of 1100 nm.

Abstract: The present invention provides an optical fiber having dispersion of ?8 ps/nm/km or less at a wavelength of 1460 nm including a reference layer which is a reference of a refractive index profile and at least three glass layers that exist inside the reference layer, characterized in that when it is assumed that the maximum relative refractive index difference of the first glass layer formed innermost of the at least three glass layers with respect to the reference layer is ?1, the relative refractive index difference of the second glass layer formed second from the inside with respect to the reference layer is ?2, the relative refractive index difference of the third glass layer formed third from the inside with respect to the reference layer is ?3 and the relative refractive index difference of the reference layer with respect to pure quartz glass is ?C, ?1>?3>?2, ?1?1.0% and ?C<0 are satisfied, and further provides an optical-module and a Raman amplifier using the optical fiber.

Abstract: An optical fiber has a Raman gain efficiency with a pump power at 1450 nanometers of equal to or more than 4 m/W, and a ratio of a nonlinear parameter ? at a wavelength of 1550 nanometers to the Raman gain efficiency with a pump power of 1450 nanometers is equal to or less than 3.

Abstract: An optical fiber for optical amplification, characterized in that a full width at half maximum of gain spectrum is 45 nm or more; and a maximum value of power conversion efficiency is 80% or more. A method for producing a rare earth element-doped glass for use in manufacturing the optical fiber, which comprises a deposition step of depositing fine silica glass particles and a co-dopant (a) to prepare an aggregate of fine silica glass particles doped with the co-dopant (a); and a immersion step of immersing the aggregate of fine silica glass particles prepared in the deposition step in a solution containing the rare earth element and the co-dopant (b) to thereby dope the aggregate of fine silica glass particles with the rare earth element component and the co-dopant (b).

Abstract: The present invention provides an optical fiber having a compensation function of the dispersion characteristic of an optical transmission line in S-band, and preferably has a filter function for cutting off wavelengths exceeding S-band. The optical fiber of the present invention has three-layered glass layers having different compositions between neighboring layers. When the maximum relative refractive index difference of a first glass layer (1) formed at the innermost of the optical fiber to a third glass layer (3) (standard layer) is represented by &Dgr;1, and the minimum relative refractive index difference of a second glass layer (2) as a second layer from the innermost of the optical fiber to the standard layer is by &Dgr;2, the following inequalities are satisfied: 1.0%≦&Dgr;1≦3.0%, and −1.0%≦&Dgr;2≦−0.4%. The dispersion value at the set wavelength of the S-band is set to −8 ps/nm/km.

Abstract: A first dispersion compensation fiber and a second dispersion compensation fiber are serially connected to constitute a dispersion compensation module, the first dispersion compensation fiber having a negative dispersion value and a negative dispersion slope, and the second dispersion compensation fiber having a negative dispersion value and a negative dispersion slope different from the negative dispersion value and the negative dispersion slope that the first dispersion compensation fiber has. The dispersion slope that first dispersion compensation fiber presents a change convex to the upward direction following a wavelength change. The dispersion slope that the second dispersion compensation fiber presents a change convex to the downward direction following a wavelength change. The transmission optical fiber is connected to the dispersion compensation module.

Abstract: An optical fiber, which is employed as a transmission line of an optical communication system, has a cable-cutoff wavelength of not longer than 1430 nanometers at the wavelength of 1450 nanometers, a mode-field diameter of not less than 7 micrometers and not more than 9 micrometers, a transmission loss of not more than 0.285 dB/km, and a dispersion of 0.1 to 4 ps/nm/km.