Abstract: The present invention aims at providing a Raman amplifier and an optical transmission system, capable of reducing characteristic deterioration to be caused by excitation lights mixedly existing within a wavelength band of signal lights. To this end, the Raman amplifier of the present invention comprises an excitation light source that generates excitation lights having a wavelength band overlapped with a wavelength band of the signal lights, a multiplexing unit that supplies the excitation lights to an optical transmission path, and an optical filter that suppresses optical components which are included in lights propagated through an optical transmission path and are of the same wavelengths as those of the excitation lights.

Abstract: An optical communication system which includes a transmission path through which a light is transmitted to a specific point, such as to a receiver. The transmission path includes a plurality of sections so that the light travels through the sections to the specific point. Each section overcompensates for dispersion produced in the respective section for the light so that an amount of dispersion for the light at the specific point is substantially zero.

Abstract: A transfer rack 15 loaded with a seriate number of component supply cassettes 14 to be handled collectively is carried and retained on a truck 61 so that it can be taken in and out of the truck 61. The transfer rack 15 is passed between the truck 61 and a component supply section 8. Thus, the withdrawal of the transfer rack 15 from the component supply section 8 to the truck 61 and the delivery of the transfer rack 15 to the component supply section 8 are executed in a timely manner so as to change the component supply cassettes 14 at the component supply section 8. The transfer rack 15 delivered to the component supply section 8 is positioned by operating an automatic positioning means at the component supply section 8 in a direction in which it is loaded and unloaded and in a direction perpendicular to the direction in which it is loaded and unloaded.

Abstract: Signal light output from a signal light generator of a light transmitter is synchronous polarization scrambled in a polarization scrambler in accordance with a modulation signal of a repetition frequency fo which approximately coincides with bit rate, and then transmitted to an optical receiver via a transmission system. The optical receiver photoelectric converts and amplifies the received signal light and then sends this to a band reject filter. The band reject filter intercepts only the noise component of a repetition frequency fo and noise components in the vicinity thereof which are produced by the synchronous polarization scrambling, while other signal components are sent to an equalizing filter and decision circuit. As a result, there is provided an optical communication system and reception apparatus wherein the noise component produced at the time of transmitting the synchronous polarization scrambled signal light is reduced so that deterioration of reception characteristics is prevented.

Abstract: The present invention is applied to an optical transmission system. The Raman amplifier comprises a light source unit generating pumping light for amplifying wavelength-multiplexed signal light, in which a plurality of wavelengths including a wavelength band of the wavelength-multiplexed signal light are arranged, a transmission path propagating the wavelength-multiplexed signal light and pumping light from the light source unit, and amplifying the wavelength-multiplexed signal light, a pumping light supplying unit supplying the pumping light to the transmission path, and a filter narrowing a spread of a spectrum of the pumping light arranged inside the wavelength band of the wavelength-multiplexed signal light and outputting it to the pumping light supplying unit. By this, the transmission capacity increases, while degradation of the transmission characteristic due to linear crosstalk and non-linear crosstalk suppresses.

Abstract: The present invention has an object to provide an optical transmission technology using Raman amplification wherein a supervisory signal transferred among a plurality of optical transmission apparatuses is superimposed on a main signal light by using a pumping light for Raman amplification. To this end, a Raman amplifier applied with the optical transmission method of the present invention, is provided with a supervisory signal superimposing section for superimposing a supervisory signal transferred among the optical transmission apparatuses on at least one of a plurality of pumping lights of different wavelengths to be supplied to a Raman amplification medium via a multiplexer from a pumping light generating section, thereby transmitting the main signal light propagated through the Raman amplification medium to be Raman amplified, which is superimposed with the supervisory signal.

Abstract: The present invention relates to an apparatus for hydrolyzing and recycling polyisocyanate derivatives having at least one isocyanato group and/or a group derived from an isocyanato group as target compounds to be hydrolyzed into raw materials or derivatives thereof for the target compounds, the apparatus including: a hydrolyzer for bringing only pressurized water in a liquid state at a temperature of 190 to 370° C. into contact with the target compounds in the reactor to hydrolyze the target compound; and a post-processor for conducting post-processings such as dewatering, addition, distillation, separation, and liquid separation for a hydrolyzed reaction product discharged from the reactor.

Abstract: A transfer rack 15 loaded with a seriate number of component supply cassettes 14 to be handled collectively is carried and retained on a truck 61 so that it can be taken in and out of the truck 61. The transfer rack 15 is passed between the truck 61 and a component supply section 8. Thus, the withdrawal of the transfer rack 15 from the component supply section 8 to the truck 61 and the delivery of the transfer rack 15 to the component supply section 8 are executed in a timely manner so as to change the component supply cassettes 14 at the component supply section 8. The transfer rack 15 delivered to the component supply section 8 is positioned by operating an automatic positioning means at the component supply section 8 in a direction in which it is loaded and unloaded and in a direction perpendicular to the direction in which it is loaded and unloaded.

Abstract: A screen printing method and apparatus for printing a circuit pattern corresponding to that of a stencil (4), onto a print-object article (1) placed on an ascendable/descendable positioning stage (2), through moving a squeegee (5a, 5b) horizontally while the squeegee is pushed in on the stencil so that print paste (9) is printed to the article via the stencil. The squeegee is lifted to an extent of a push-in stroke, to which the squeegee has been pushed in on the stencil, and thereafter the article is separated away from the stencil by moving the stage downward. The board is classified into first and second areas (121, 120) where values of opening sizes of the stencil along a squeegee moving direction are smaller than and not smaller than a threshold, and a speed of the squeegee at the first area is made slower than that at the second area.

Abstract: An optical transmission system for transmitting an optical signal through an optical fiber transmission line includes a first optical fiber transmitting the optical signal and having a first zero-dispersion wavelength shorter than a wavelength of the optical signal, and a second optical fiber transmitting the optical signal from the first optical fiber and having a second zero-dispersion wavelength longer than the wavelength of the optical signal. A first nonlinear effective cross-sectional area of the first optical fiber is larger than a second nonlinear effective cross-sectional area of the second optical fiber.

Abstract: The present invention relates to a Raman amplification optical fiber and the like comprising a structure which can Raman-amplify signal light including a plurality of wavelength components at a high efficiency and effectively restrain signal waveforms from deteriorating due to influences of nonlinear optical phenomena, while improving the degree of freedom in the design of optical fiber transmission lines and Raman amplifiers. As characteristics at each wavelength of signal light, the Raman amplification optical fiber has a chromatic dispersion with an absolute value of 6 ps/nm/km or more but 20 ps/nm/km or less, and an effective area Aeff of 20 &mgr;m2 or less, preferably less than 15 &mgr;m2. More preferably, as a characteristic at each wavelength of signal light, the Raman amplification optical fiber has a Raman gain coefficient GR/Aeff of 0.005 (W·m)−1 or more.

Abstract: A plurality of optical repeaters are provided on a transmission line between an optical transmitting station and an optical receiving station. A combined transmission line section is provided between optical repeaters. The combined transmission line section is composed of the first optical fiber, which is a positive-dispersion fiber, and the second optical fiber, which is a negative-dispersion fiber. Signal light is inputted to the first optical fiber in each combined transmission line section. Each optical repeater inputs pump light to the second optical fiber.

Abstract: An optical transmission line including first, second and third fibers so that an optical signal travels through the first, second and third fibers, in order. The first fiber has a positive dispersion for a wavelength of the optical signal. The second fiber has a negative dispersion for the wavelength of the optical signal and a mode field diameter smaller than a mode field diameter of the first fiber. The third fiber has a mode field diameter smaller than the mode field diameter of the second fiber. Pump light is provided to the third fiber so that Raman amplification occurs in the transmission line.

Abstract: A filling squeegee and a scraping squeegee are provided in a printing apparatus. The filling squeegee is moved without contacting a surface of a mask in order to fill a solder paste into openings of the mask. Unnecessary solder paste on the surface of the mask is scraped by the scraping squeegee. The solder paste is prevented from being improperly filled in or scraped from the openings even if a speed of the squeegee is increased, so that the solder paste can be printed stably on circuit board.

Abstract: A clutch apparatus includes a clutch disk; a pressure plate for moving the clutch disk through application of pressure; a diaphragm spring for applying a force to the pressure plate so as to urge the pressure plate toward a flywheel; a release bearing for pressing a central portion of the diaphragm spring; a release fork; and an actuator. The pressure plate and an outer circumferential portion of the diaphragm spring are in contact with each other via taper portions of the pressure plate and an adjust wedge member. The clutch apparatus counts the number of clutch operations. In order to obtain a desirable press-contact load according to the counted number of clutch operations, the adjust wedge member is rotated with respect to the pressure plate to thereby modify the attitude of the diaphragm spring.

Abstract: An optical communication system which includes a transmission path through which a light is transmitted to a specific point, such as to a receiver. The transmission path includes a plurality of sections so that the light travels through the sections to the specific point. Each section overcompensates for dispersion produced in the respective section for the light so that an amount of dispersion for the light at the specific point is substantially zero.

Abstract: An optical communication system which includes a transmission path through which a light is transmitted to a specific point, such as to a receiver. The transmission path includes a plurality of sections so that the light travels through the sections to the specific point. Each section overcompensates for dispersion produced in the respective section for the light so that an amount of dispersion for the light at the specific point is substantially zero.

Abstract: A plurality of Raman amplifiers are positioned on a transmission line over which a multi-wavelength light is transmitted. Each of the Raman amplifiers uses a plurality of pump lights &lgr;1 through &lgr;4. When a fault occurs in a pump light source producing the pump light &lgr;3 in a particular Raman amplifier among the plurality of Raman amplifiers, the power of the pump light &lgr;3 is raised in another or other Raman amplifiers.

Abstract: A plurality of pump lights are appropriately located in a wavelength band &lgr;1 to &lgr;3. The width of the wavelength band &lgr;1 to &lgr;3 is wider than a Raman shift amount. Gain is obtained in a wavelength band &lgr;2 to &lgr;3 by the plurality of pump lights located in the wavelength band &lgr;1 to &lgr;2. Gain is obtained in a wavelength band &lgr;3 to &lgr;4 by the plurality of pump lights located in the wavelength band &lgr;2 to &lgr;3. As a result, gain can be obtained in a wavelength band &lgr;2 to &lgr;4. A plurality of signal lights are located in the wavelength band &lgr;2 to &lgr;4. The deviation of gain can be adjusted by controlling the power of each of the plurality of pump lights.

Abstract: There are provided a wavelength dispersion compensating method of reducing distortion of a transmitted waveform due to cross phase modulation in an optical transmission path, and an optical transmission system utilizing the method. To this end, the wavelength dispersion compensating method of the present invention sets the wavelength dispersion characteristic of the optical transmission path such that the time delay amount to occur between light signals of adjacent two wavelengths due to wavelength dispersion such as in one repeating section in the transmission path, to become ½ times of a bit interval, for the optical transmission path having transmission loss.