Abstract: The present invention relates to a compact dispersion compensator and the like. The dispersion compensator comprises a housing and an optical fiber coil. The optical fiber coil has a coiled part constituted by a dispersion-compensating optical fiber wound like a coil while being in a bundle state with its winding distortion substantially eliminated. The housing is filled with a resin surrounding the coiled part of the optical fiber coil, whereas the coiled part is held by the resin. The dispersion-compensating optical fiber constituting the optical fiber coil has a chromatic dispersion of ?140 ps/nm/km or less at a wavelength of 1.55 ?m, whereas the housing has a volume of 500 cm3 or less. This configuration allows the dispersion compensator to attain an accumulated chromatic dispersion of ?1200 ps/nm/km or more but less than ?600 ps/nm at a wavelength of 1.55 ?m.

Abstract: The present invention relates to a wavelength converter of structure enabling generation of converted light with high power even with a large difference between the wavelength of pumping light and the zero-dispersion wavelength. The wavelength converter includes an optical fiber having a dispersion slope whose absolute value at the wavelength of 1550 nm is 0.01 ps/nm2/km or less, for example.

Abstract: A invented computer system has a plurality of computer boards; a plurality of terminals, each of which is coupled to each of the computer boards respectively via a network; a storage device having a plurality of storage areas, which is coupled to each of the computer boards; and a management computer; and wherein the management computer manages a correspondence between a user information and the storage area, and when a use request of the computer board is transmitted from a terminal, the management computer selects a usable computer board to turn on a power, reads information necessary to start the computer board from the storage corresponding to the transmitted user information, allows the computer board to start based on the read information, and notifies the terminal of information on the started computer board and identification information on the network allocated to the started computer board.

Abstract: An oscillator and a radar apparatus that includes a resonator electro-magnetically connected to a micro strip line and a rotor connected to the resonator by capacitance. The bottom surface of the rotor has a changing height in the circumferential direction of the rotor. As the rotor is rotated, an actual oscillation frequency is recognized from the rotating angle of the rotor when an output of a detector has a peak. A modulation voltage supplied to a VCO is corrected in accordance with the result.

Abstract: An optical fiber is formed for use in optical communications systems capable of transmitting and receiving a large volume of information. The optical fiber has a chromatic dispersion of at least 4 ps/nm/km and at most 15 ps/nm/km at a wavelength of 1,550 nm, a transmission loss of at most 0.190 dB/km at a wavelength of 1,530 to 1,570 nm, and an effective cutoff wavelength measured by the 2-meter method of 1610 nm or more. An optical transmission line and an optical communications system are structured by using the foregoing optical fiber.

Abstract: In a client/server architecture system, a device management system having the function of safely sharing a device without compromising user convenience is provided. The device is coupled to a terminal that the user uses or a hub coupled to a network. A device management manager having a device driver function and communication function installed on the terminal or the like, a virtual device manager having a device driver function and communication function installed on the server, and an authentication server that manages access permission for the device allow the device to be virtually available as in the case of the device directly coupled to the server while managing the access to the device.

Abstract: A random seed scramble for preventing the deterioration of a medium is applied to the next generation optical disk. A seed is stored to a BIS area. ID or an EDC is checked to hold interchangeability before and after scramble release. When no error is generated in data before the scramble release, it is recognized as an unscrambled disk. In contrast to this, when no error is generated in data after the scramble release, it is recognized as a scrambled disk. An information storing area showing an area to be rewritten by performing the scramble and an area to be rewritten without performing the scramble is arranged.

Abstract: The present invention provides a light-receiving device that may escape the device from the breakdown thereof and may suppress an optical loss. The light-receiving device of the invention includes a surface to sense the light and a thin film made of PbSe nano-particles, diameters of which are smaller than 20 nm. This thin film operates as an optical fuse, so the device may be escaped from the breakdown thereof. Moreover, the thin film is disposed directly onto the light-sensing surface of the device, the optical loss cause between the thin film and the sensing surface may be suppressed.

Abstract: Disclosed is a secure remote access system for improving convenience of a user by utilizing a storage device including an anti-tampering device as a user authentication device in the secure remote access system for making access and execution of job while a user is making the encrypted communication to a server from an unspecified client. Usability can be improved and thereby the job executing function can be used smoothly at the internal and external sides of the working office by providing a server client system where the server can be manipulated remotely by distributing a storage device loading the authorized anti-tampering device to users, connecting the storage device to unspecified clients by users, and using the authentication information and application stored in the storage device. A remote access system having improved security and convenient during usage of client from the user can also be provided by reducing the secret information remaining in the manipulated client.

Abstract: A high-frequency oscillation apparatus wherein an oscillation signal output from a voltage controlled oscillator (VCO) is transferred through a transfer line to a resonator and the resonator is excited. The resonator is coupled with a second transfer line and an RF signal having a level corresponding to the frequency of the oscillation signal is transferred through the second transfer line. When the resonant frequency of the resonator is set to a frequency higher than the oscillation-frequency modulation range of the VCO, the oscillation frequency and the RF-signal level have one-to-one correspondence. A detector detects the RF signal and outputs to a control section. The control section compensates a control voltage signal applied to the VCO according to the detected-signal level, and outputs the control voltage signal to the VCO to compensate the oscillation signal of the VCO.

Abstract: The present invention relates to an optical fiber or the like which allows more precise compensation for the chromatic dispersion of a transmission optical fiber over a broad wavelength band. The optical fiber has a chromatic dispersion of ?100 ps/nm/km or less in a wavelength band of 1535 to 1565 nm, 1565 to 1610 nm, 1554 to 1608 nm or 1535 to 1610 nm. In particular, the chromatic dispersion profile of the fundamental mode of this optical fiber defined by the orthogonal coordinate system of the wavelength and chromatic dispersion value has a shape such that, over the entire wavelength band except for the shortest and longest wavelengths thereof, the chromatic dispersion values on the chromatic dispersion profile are respectively located on the minus side of the associated chromatic dispersion values on a straight line connecting the chromatic dispersion values at the shortest and longest wavelength.

Abstract: The present invention provides a line transition and a method for manufacturing the same. The line transition is constructed such that a planar circuit can be arranged in the direction parallel to the propagation direction of electromagnetic waves propagating through a solid waveguide, the coupling characteristics of the solid waveguide with the planar circuit formed on a dielectric substrate are not influenced by the assembly precision of the waveguide and the circuit, and the line transition characteristics are not affected by a variation in manufacturing the dielectric substrate. Notches are formed at the edges of the dielectric substrate in the vicinities of coupled-line pattern segments formed on a dielectric substrate. The notches are formed by punching through holes in a ceramic green sheet serving as a motherboard, firing the motherboard, and cutting the motherboard using dicing lines passing through the through holes.

Abstract: A waveguide, a high-frequency circuit, and a high-frequency circuit device having the waveguide are provided. The waveguide includes two conductor plates each of which has a surface having a groove. At least one of the conductor plates has protrusions extending from the surface at both sides of the groove. The two conductor plates are in contact with each other such that the grooves face each other. Screws disposed between the protrusions and bumps, which are formed outside the protrusions on the conductor plate, fasten the conductor plates with a predetermined pressure.

Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

Abstract: An optical fiber capable of compensating in the L-band both the chromatic dispersion and dispersion slope of a positive-dispersion optical fiber, an optical transmission line incorporating the optical fiber, and an optical communications system incorporating the optical transmission line. An optical communications system 1 comprises an optical transmission line 10, an optical transmitter 20, and an optical receiver 30. The optical transmission line 10 comprises an optical fiber 11 and an optical fiber 12 that are mutually fusion-spliced. The optical fiber 12 has at a wavelength of 1,590 nm a chromatic dispersion, D2, and a dispersion slope, S2, that satisfy the formulae ?200 ps/nm/km?D2??50 ps/nm/km, and 0.009/nm?S2/D2.

Abstract: An optical fiber comprising a core region 100 doped with Cl which raises the refractive index; and a cladding region 200, provided at the outer periphery of the core region 100, having a cladding layer 201 doped with F which lowers the refractive index is formed. The cladding region 201 to become the outermost cladding layer is configured such that the doping amount of F successively decreases within an outer peripheral part 205 including the outer periphery thereof to a predetermined doping amount which is the minimum doping amount of F within the cladding layer 201. Therefore, the stress within the optical fiber is dispersed into the outer peripheral part 205 having an enhanced viscosity, whereby the stress concentration into the core is suppressed. Since the favorable tension range at the time of drawing the optical fiber becomes wider at this time, tension control is facilitated.

Abstract: An optical transmission line and an optical transmission system, the handling of which is easy, and in which transmission loss and the absolute value of cumulative chromatic dispersion is small over a wide wavelength range are proposed. The optical transmission system has a transmitter, a receiver and an optical transmission line. The optical transmission line has an optical transmission fiber and a dispersion-compensating fiber. The optical transmission fiber has a chromatic dispersion of +4˜+10 ps·nm?1·km?1 and a dispersion slope of 0˜+0.04 ps·nm?2·km?1 at the 1550 nm wavelength and is installed in a relay section. The dispersion compensating fiber has a chromatic dispersion of ?40 ps·nm?1·km?1 or less and a dispersion slope of ?0.10 ps·nm?2·km?1 or less at the 1550 wavelength and is wound in a coil to be put in a repeater.

Abstract: The present invention relates to an optical transmission line and the like having a chromatic dispersion with a small absolute value as a whole within a signal wavelength band including S, C, and L bands. This optical transmission line comprises a single-mode optical fiber and a dispersion-compensating optical fiber which are connected to each other; and has, as characteristics of the whole optical transmission line at a wavelength of 1550 nm, a chromatic dispersion with an absolute value of 4 ps/nm/km or less, and a dispersion slope of ?0.015 ps/nm2/km or more but less than 0 ps/nm2/km. Its chromatic dispersion has a maximum value within a wavelength range of 1450 to 1530 nm, and a minimum value within a wavelength range of 1570 to 1620 nm.

Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

Abstract: The present invention relates to an optical fiber which enables favorable optical communications in 1.3-?m and 1.55-?m wavelength bands, and an optical transmission system including the same. The optical fiber according to the present invention has only one zero-dispersion wavelength within a wavelength range of 1.20 ?m to 1.60 ?m, the zero-dispersion wavelength existing within a wavelength range of 1.37 ?m to 1.50 ?m , and has a positive dispersion slope at the zero-dispersion wavelength, thereby enabling favorable optical communications utilizing each signal light in the 1.3-?m and 1.55-?m wavelength bands sandwiching the zero-dispersion wavelength.