Abstract: The present invention relates to an analog optical transmission system having a construction for expanding an analog transmittable distance. The analog optical transmission system includes: a light transmitter outputting analog optical signals such as image signals modulated in accordance with electrical signals multiplexed on a frequency domain; a transmission line including a SMF of 20 km or less in the total length; and a light receiver. A dispersion compensating fiber compensating for the chromatic dispersion of the transmission line is arranged on the transmission line, and the dispersion compensating fiber satisfies one of the first condition that the chromatic dispersion is set at ?250 ps/nm/km or less and a length is set at 1.1 km or less, and the condition that the chromatic dispersion is set at ?330 ps/nm/km or less and a length is set at 1.2 km or less. Optical suppressing devices reducing the MPI noise are arranged at the end portion of the dispersion compensating fiber.

Abstract: The present invention relates to an analog optical transmission system having a construction for expanding an analog transmittable distance. The analog optical transmission system includes: a light transmitter outputting analog optical signals such as image signals modulated in accordance with electrical signals multiplexed on a frequency domain; a transmission line including a SMF of 20 km or less in the total length; and a light receiver. A dispersion compensating fiber compensating for the chromatic dispersion of the transmission line is arranged on the transmission line, and the dispersion compensating fiber satisfies one of the first condition that the chromatic dispersion is set at ?250 ps/nm/km or less and a length is set at 1.1 km or less, and the condition that the chromatic dispersion is set at ?330 ps/nm/km or less and a length is set at 1.2 km or less. Optical suppressing devices reducing the MPI noise are arranged at the end portion of the dispersion compensating fiber.

Abstract: An operation assist apparatus includes a display device installed in an operator's cab of a construction machine, at which at least operating procedures for the construction machine are displayed with text and illustrations; an image processing device that generates images; and a control device that engages the image processing device to generate an image of an operating procedure corresponding to an operation of the construction machine and engages the display device to display the image generated by the image processing device.

Abstract: An apparatus and method for measuring polarization mode dispersion (PMD) using a polarization mode dispersion measuring device, comprising an FSF laser generating frequency chirped light, an optical amplifier amplifying the frequency chirped light, an offset circuit, a ?/2 plate, a beam splitter, an analyzer retrieving polarization components measured from each light wave after propagating through the fast axis and the delay axis of the optical fiber under test, a lens, a photodetector detecting a light wave passed through the lens, and an RF spectrum analyzer observing a spectrum waveform of the light wave. The frequency chirped light, after propagating through the optical fiber under test and passing through the analyzer, is detected and the variation in beat frequency is measured to determine a PMD value.

Abstract: The present invention relates to an optical transmission system having a structure to enable signal transmission while maintaining superior transmission characteristics over a broader wavelength band. Signal light outputted from a signal light source has a positive chirp, and propagates through a transmission line fiber to an optical receiver, after being Raman-amplified by a lumped Raman amplifier. The lumped Raman amplifier includes, as a Raman amplification fiber, a high-nonlinearity fiber having a negative chromatic dispersion at a wavelength of the signal light and intentionally generating a self-phase modulation therein. The positive chirp of the signal light propagating through the high-nonlinearity fiber is effectively compensated by both of the negative chromatic dispersion and the self-phase modulation generated in the high-nonlinearity fiber.

Abstract: The present invention relates to an optical fiber transmission line and the like comprising a structure for enabling repeating sections to become further longer. The optical fiber transmission line comprises first and second optical fibers successively disposed along the traveling direction of signal light, and an optical multiplexer for supplying Raman amplification pumping light to one of the first and second optical fibers. The first and second optical fibers are optically connected to each other. The second optical fiber has an effective area smaller than that of the first optical fiber, and a chromatic dispersion and a length which are different from those of the first optical fiber. In particular, the respective lengths of the first and second optical fibers are appropriately regulated so as to effectively suppress nonlinear phenomena other than Raman amplification.

Abstract: The present invention relates to a practical optical amplification module and the like realizing a wide-band gain spectrum with a small relative gain non-uniformity in L band. Pumping light from a pumping light source is supplied to a Bi type EDF by way of an optical coupler. Multiplexed signal light of L band inputted by way of an input end reaches the Bi type EDF by way of an optical coupler, an optical isolator, and an optical coupler, and is collectively amplified in the Bi type EDF. The multiplexed signal light amplified in the Bi type EDF is outputted from an output end by way of an optical coupler, an optical isolator, and an optical coupler.

Abstract: The present invention relates to an optical transmission system and others with excellent noise characteristics. The optical transmission system is provided with an optical fiber transmission line through which signal light propagates, an optical device, and a Raman amplifier placed upstream of the optical device. The optical device functions as an element that degrades a noise characteristic in a signal wavelength band from the long wavelength side toward the short wavelength side when a desired gain is given to the signal light propagating in the optical fiber transmission line. On the other hand, the Raman amplifier is configured so as to adjust optical powers of respective pumping channels in pumping light and thereby Raman-amplify the signal light so that optical powers of the signal channels increase from the long wavelength side toward the short wavelength side in the signal wavelength band, in order to improve the noise characteristic of the whole optical fiber transmission line.

Abstract: This invention provides an optical transmission system which allows to perform high-quality transmission of each of a plurality of signal channels multiplexed. In the optical transmission system, signal light in which a plurality of signal channels with an optical frequency spacing of 400 GHz or more but 12.5 THz or less is transmitted from an optical transmitter to a Raman amplifier through an optical fiber transmission line. In the Raman amplifier, pumping light from a pumping light source unit is supplied to an optical fiber through an optical coupler. The multiplexed signal light inputted to the Raman amplifier arrives at the optical fiber through an optical isolator and optical coupler, and Raman-amplified by the optical fiber. The Raman-amplified multiplexed signal light is outputted from the Raman amplifier through an optical coupler and optical isolator.

Abstract: The present invention relates to an optical fiber transmission line and the like comprising a structure for enabling repeating sections to become further longer. The optical fiber transmission line comprises first and second optical fibers successively disposed along the advancing direction of signal light, and an optical multiplexer for supplying Raman amplification pumping light to one of the first and second optical fibers. The first and second optical fibers are fusion-spliced to each other, whereas at least one of them has a core region substantially made of pure silica glass. The second optical fiber has an effective area smaller than that of the first optical fiber, and a chromatic dispersion and a length which are different from those of the first optical fiber. In particular, the respective lengths of the first and second optical fibers are appropriately regulated so as to effectively suppress nonlinear phenomena other than Raman amplification.

Abstract: A high-voltage variable resistor includes a circuit section contained in an insulating casing, a snap-in terminal inserted in a terminal base portion of the casing and connected to an output portion of the circuit section, and an output connecting electrode inserted in the terminal base portion from a direction orthogonal to the snap-in terminal and press-fitted in and connected to the snap-in terminal. The terminal base portion of the casing has an insertion groove for guiding and inserting the snap-in terminal, an insertion hole for guiding and inserting the output connecting electrode, and a relief groove formed on a side face of the insertion groove intersecting the insertion hole. The insertion groove, the insertion hole, and the relief groove are simultaneously formed by a metal mold of the structure to be pierced.

Abstract: The present invention relates to an optical fiber transmission line and the like comprising a structure for enabling repeating sections to become further longer. The optical fiber transmission line comprises first and second optical fibers successively disposed along the advancing direction of signal light, and an optical multiplexer for supplying Raman amplification pumping light to one of the first and second optical fibers. The first and second optical fibers are fusion-spliced to each other, whereas at least one of them has a core region substantially made of pure silica glass. The second optical fiber has an effective area smaller than that of the first optical fiber, and a chromatic dispersion and a length which are different from those of the first optical fiber. In particular, the respective lengths of the first and second optical fibers are appropriately regulated so as to effectively suppress nonlinear phenomena other than Raman amplification.

Abstract: The present invention relates to an optical fiber transmission line and the like comprising a structure for enabling repeating sections to become further longer. The optical fiber transmission line comprises first and second optical fibers successively disposed along the traveling direction of signal light, and an optical multiplexer for supplying Raman amplification pumping light to one of the first and second optical fibers. The first and second optical fibers are optically connected to each other. The second optical fiber has an effective area smaller than that of the first optical fiber, and a chromatic dispersion and a length which are different from those of the first optical fiber. In particular, the respective lengths of the first and second optical fibers are appropriately regulated so as to effectively suppress nonlinear phenomena other than Raman amplification.

Abstract: An optical transmission line and an optical communication system for high-quality transmission of signal light using distributed Raman amplification are disclosed. In an optical communication system 1, an optical transmission line 10 including a first optical fiber 11 and a second optical fiber 12, which are connected to each other by means of fusion, is disposed between an optical repeater 30 and an optical repeater 40. The effective core area of the optical fiber 11 is smaller than the effective core area of the optical fiber 12. The absolute value of the chromatic dispersion of the optical fiber 12 is smaller than that of the optical fiber 11. When the lengths of the optical fibers 11 and 12 are represented by L1 and L2, respectively, the ratio L2/(L1+L2) is not less than 0.5.

Abstract: A high-voltage variable resistor includes a circuit section contained in an insulating casing, a snap-in terminal inserted in a terminal base portion of the casing and connected to an output portion of the circuit section, and an output connecting electrode inserted in the terminal base portion from a direction orthogonal to the snap-in terminal and press-fitted in and connected to the snap-in terminal. The terminal base portion of the casing has an insertion groove for guiding and inserting the snap-in terminal, an insertion hole for guiding and inserting the output connecting electrode, and a relief groove formed on a side face of the insertion groove intersecting the insertion hole. The insertion groove, the insertion hole, and the relief groove are simultaneously formed by a metal mold of the structure to be pierced.

Abstract: A bank quantity adjusting device for an extruder capable of accurately controlling a bank quantity regardless of a difference in composition of a material to be extruded. The bank quantity adjusting device includes a pressure sensor 13 for detecting a bank pressure between an outlet 7 of an extruder body 1 provided with material extruding screws 3 and a roller die 2 provided before the outlet 7, and a control device 15 for controlling one or both of a screw speed and a roller die speed according to a difference between the bank pressure detected by the pressure sensor 13 and a set target pressure.

Abstract: An input device for sewing machines comprising a means for making visible the sewing pattern up to the inflection point immediately followed by the inflection point to be modified to facilitate the modification of the sewing pattern, a means for inputting the coordinate data of the inflection point to be modified, a means for indicating the contents of the modification, and a means for operating the contents of the modification thus indicated under a predetermined control.

Abstract: An input device for sewing machines is disclosed which reads from a memory circuit an original sewing pattern which has been already stored, enlarging or reducing the coordinate data of the original sewing pattern in a desired scale, and prepare the coordinate data of sewing points between the flexing points thus obtained by enlargement or reduction in accordance with a desired stitch length data or stitch number data. The input device is adapted to convert the coordinate data of the original sewing pattern to the coordinate data calculated with the central point of a crank member of a work holder with the crank member as the origin and enlarge or reduce the coordinate data of the flexing points other than the starting point and the ending point of sewing in a desired scale, when the original sewing pattern is for a work holder with a crank member.

Abstract: A golf-swing-practicing device comprising a flexible shaft having a weight attached to one end of the shaft, the shaft being composed of a composite core member having a plurality of strands twisted around the core, and each of the strands being formed of a plurality of steel wires twisted together. The composite core member includes a flexible core element formed of fibers and a non-flexible core element such as iron arranged in axial end-to-end alignment with each other. The shaft and the weight assembly are provided with a covering of synthetic resin, synthetic rubber or synthetic leather. Through repeated practice, whether indoors or out-of-doors, with use of the device the user can empirically master the various techniques for hitting long shots with a maximum power at impact for hitting the ball with proper timing, and for eliminating wild shots.