Abstract: In a communication system wherein a station transceiver and a plurality of nodes communicate in a TDM system through a signal transmission line, at least apart of the line is shared, a method to judge nodes performing normal operation from the station transceiver comprises a request step to request a return of a test pattern by transmitting a trigger signal for a designated node in the plurality of nodes, a correlation process step to process correlation between a received signal in a timeslot assigned to the designated node and a reference pattern corresponding to the designated node, and a judging step to judge whether the designated node is a normal node according to the correlation process result.

Abstract: An optical repeater monitoring system, according to the invention, comprises an oscillating source, a reference signal transmitter for transmitting a reference signal of a predetermined frequency generated from an output of the oscillating source to a first optical fiber, and an optical repeater. The optical repeater has a first photodetector for converting light from the first optical fiber into an electrical signal, a reference signal extractor for extracting a component of the reference signal from an output of the first photodetector, a carrier generator for generating a carrier from an output of the reference signal extractor, a monitor signal modulator for modulating the carrier generated by the carrier generator with a monitor signal showing a operating state of the optical repeater, a transmitter for transmitting an output of the monitor signal modulator to a second optical fiber.

Abstract: An electroforming apparatus comprising a container unit for storing the plating solution, a cathode part placed in the container unit and for holding an object to-be-plated and an anode part placed in the container unit face-to-face with the cathode part, wherein a current-conductive opening of the anode part is formed to have an area larger than that of a current-conductive opening of the cathode part.

Abstract: The soliton pulse compression optical fiber comprises a core and a clad that surrounds the core for compressing the injected light pulse in width. The maximum relative index difference between the core and the clad is between about 1.2% and 2.5%. The core diameter of the soliton pulse compression optical fiber varies along the length of the soliton pulse compression optical fiber and the core has a step-like refractive index distribution. The optical fiber perform of the soliton pulse compression optical fiber comprises a core preform, which is to be a core of the soliton pulse compression optical fiber, and a clad preform that surrounds the core preform. The maximum relative index difference between the core perform and the clad preform is also between about 1.2% and 2.5%.

Abstract: An optical digital regenerator for digitally regenerating an input signal in an intact optical state. A first operating unit has a first probe light generator for generating a first probe light and a first optical operator for converting a waveform of the first probe light output from a first probe light generator according to an optical intensity waveform of the input signal light. A clock extractor extracts a clock component of the input signal light from a photocurrent generated by the first optical operator. A second optical operating unit has a second probe light generator for generating a second probe light pulsed in accordance with the clock output from the clock extractor and a second optical operator for sampling the second probe pulse light output from the second probe light generator.

Abstract: The object of this invention is to improve SNR in the Raman amplification. An optical fiber (10) consists of a dispersion shift fiber in which a zero dispersion wavelength is shifted to the 1.55 &mgr;m band, and an optical fiber (12) consists of a single mode optical fiber having the effective core area of 100 &mgr;m2 which is larger than that of the optical fiber (10). An optical coupler 14 is disposed at the optical signal emission end of the optical fiber (12). A laser diode (16) outputs the laser light of 1455 nm as a Raman pumping light source. The output light from the laser diode (16) is introduced into the optical fiber (12) from the back, namely in the opposite direction to that of the optical signal propagation. The ratio of the Raman gain coefficient of the optical fiber (12) to that of the optical fiber (11) should be 1/1.08 or less, preferably 1/1.1 or less.

Abstract: To improve the reliability of matrix switches of redundant configuration, a splitter (14) splits each of a plurality of input lights into two portions and applies them to corresponding input ports of matrix switches (10a and 10b). The working matrix switch (10a) connects between desired input and output ports and an optical shutter (30a) connecting to an output port (#1) is in a light transmission state. The matrix switch (10b) connects all its input ports (#1 through #8) to an output port (#1). An optical shutter (30b) connecting to an output port (#1) is in a light blocking state. A combiner (26) combines the lights which are output from the output ports (#1) of the matrix switches (10a and 10b) and transmitted through the optical shutters (30a and 30b) and also combines the output lights from the corresponding output ports (#2 through #8) of the matrix switches (10a and 10b).

Abstract: An optical waveform shaper comprising a probe light source for generating probe light with a constant amplitude, a signal copier to which input signal light of a signal wavelength and the probe light output from the probe light source is applied and which copies the signal of the input signal light onto the probe light, and an extinction ratio improver for improving the extinction ratio of output light from the signal copier is described.

Abstract: An optical repeating system includes an optical transmitter and a plurality of optical amplifying repeaters. The optical transmitter specifies a part or all of the optical amplifying repeaters, and transmits a supervisory command to the specified optical amplifying repeaters as a first sub-signal via an uplink or downlink optical transmission line. The supervisory command is a command to supervise internal circuits of the optical amplifying repeaters. Receiving the supervisory command addressed thereto via the uplink or downlink optical transmission line, the optical amplifying repeaters each transmit a supervisory signal indicating a supervisory result corresponding to the supervisory command to optical receivers via the uplink and downlink optical transmission lines as a second sub-signal. The optical system can reduce the time take to acquire the supervisory information about the plurality of the optical amplifying repeaters.

Abstract: An optical repeating system includes an optical transmitter and an optical amplifying repeater. The optical transmitter transmits a supervisory command and a control command to the optical amplifying repeater as a first sub-signal. The supervisory command is a command to supervise internal circuits of the optical amplifying repeater, and the control command is a command to control the optical amplifying repeater. The optical amplifying repeater includes multiple sub-modules each for amplifying and repeating main signals on multiple sets of optical transmission lines. When receiving the supervisory command via the optical transmission line, each sub-module transmits a supervisory signal indicating the supervisory result associated with the supervisory command to an optical receiver as a second sub-signal.

Abstract: An optical repeating system includes an optical transmitter and a plurality of optical amplifying repeaters. The optical transmitter specifies one of the optical amplifying repeaters, and transmits a supervisory command and a control command to the specified optical amplifying repeater as a first sub-signal. The supervisory command is a command to supervise internal circuits of the optical amplifying repeater, and the control command is a command to control amplification factors of optical amplifiers of the optical amplifying repeater. Receiving the supervisory command via the uplink or downlink optical transmission line, the optical amplifying repeater transmit a supervisory signal indicating a supervisory result corresponding to the supervisory command to optical receivers via the uplink and downlink optical transmission lines as a second sub-signal.

Abstract: A piston slidably fitted in a cylinder is connected to an auxiliary piston slidably fitted in an auxiliary cylinder coaxial with the cylinder through a first connecting rod. An intermediate pin provided on the auxiliary piston is connected to left and right crankshaft halves through a pair of second connecting rods. The left and right crankshaft halves are disposed outside of a piston sliding range of the cylinder with respect to the radial direction thereof. The increase of the volume of a combustion chamber corresponding to the increase of the crank angle with reference to top dead center of the piston is suppressed, and it is therefore possible to enhance the equal volume degree at the time of combustion of a mixture gas and to enhance thermal efficiency.

Abstract: An optical reception apparatus comprises an optical receiver to receive an optical signal from an optical transmission line, an error corrector to correct an error of the signal received by the optical receiver and to transmit the error-corrected signal and error rate information before error correction, a judging apparatus to judge transmission quality of the optical transmission line according to the error rate information from the error corrector and a threshold value equal to an error rate lower than an error correction limit of the error corrector, and a selective breaker to transmit the signal whose error is corrected by the error corrector in normal state and to block transmission of the signal whose error is corrected by the error corrector when the judged result by the judging apparatus indicates deterioration of the transmission quality of the optical transmission line.

Abstract: An optical crossconnect system comprises an input stage including a plurality of input matrix switches, each having a plurality of input ports and a plurality of output ports, an output stage including a plurality of output matrix switches, each having a plurality of input ports and a plurality of output ports, and an intermediate stage including a plurality of intermediate matrix switches, each having a plurality of input ports and a plurality of output ports. Each input port of each intermediate matrix switch connects to an output port which corresponds to the intermediate matrix switch, at an input matrix switch corresponding to the input port in the plurality of input matrix switches. Each output port of each intermediate matrix switch connects to an input port, which corresponds to the intermediate matrix switch, at an output matrix switch corresponding to the output port in the plurality of output matrix switches.

Abstract: An object of this invention is to regenerate optical signals in an intact optical state according to a low-speed optical clock.

Abstract: A laser diode continuously laser-oscillates and its output light is applied to an optical modulator. A pulse driver drives the optical modulator according to a data to be transmitted. A phase modulator is driven by a phase modulator driver and phase-modulates the output from the optical modulator. The polarization direction of the incident light of the phase modulator is set so that the modulation efficiency of the phase modulator becomes the maximum. The output light of the phase modulator inputs a birefringent medium and applies to an optical transmission line after transmitting the birefringent medium. The principal axis of the birefringent medium is disposed so as to be at an angle of 45° to the polarization direction of the output light from the phase modulator.

Abstract: An optical TDM multiplexing apparatus to multiplex a plurality of input signals in the optical stage in the time domain according to the invention comprise a plurality of signal light sources to generate optical signals each having a wavelength different from the others to carry each of the plurality of the input signals, a timing adjuster to adjust timings between the respective optical signals so that each optical signal output from the plurality of the signal light sources is disposed on a time slot different from the others in the time domain, an optical multiplexer to multiplex each optical signal output from the timing adjuster in the wavelength domain and a wavelength converter to convert each wavelength of the output light from the optical multiplexer into a predetermined wavelength.

Abstract: Detection of an optical pulse position uses an optical pulse string with a determined repetitive ratio and an electric clock signal with a same frequency as the repetitive ratio of the optical pulse string. A phase of the electric clock signal oscillator is shifted and supplied to an optical modulator. The optical modulator modulates the optical pulse string based on the electric clock signal and outputs a modulated optical signal. A photo detector converts the modulated optical signal output from the optical modulator to an electric signal. The phase shift amount of the electric clock signal is controlled to maximize an output from the photo detector. Additionally, a dither signal may be used in the control of the phase shift, more than the optical modulator may be employed, and/or more than color light source may be employed. The use of at least one of feed forward and feedback control provided by maximizing an output of the photo detector allows an optical pulse having a short width to be realized.

Abstract: An object of this invention is to realize satisfactory long haul transmission characteristics using two kinds of optical fibers. An optical fiber transmission line consists of a plurality of local dispersion compensating spans, wide dispersion compensating spans disposed at predetermined intervals, and optical repeating amplifiers to connect each span. The local dispersion compensating span consists of a first optical fiber with positive dispersion having an effective core area of 130 &mgr;m2 or more and a second optical fiber with a negative dispersion value of −50 ps/nm/km or less to transmit the light output from the first optical fiber. The wide dispersion compensating span consists of a third optical fiber having the same configuration and composition with the first optical fiber.

Abstract: To increase thermal efficiency by increasing the degree of constant volume of a fuel-air mixture at the time of combustion in an internal combustion engine. In an internal combustion engine, a piston slidably fitted in a cylinder is connected to a crankshaft via a connecting rod, and a cylinder head in which a combustion chamber is defined is disposed between the piston and the crankshaft. As compared with a background art internal combustion engine in which a combustion chamber is disposed opposite to a crankshaft with a piston located therebetween, a ratio of an increased amount of the volume of the combustion chamber to an increased amount of a crank angle of the piston from the top dead center position can be suppressed at a small value. As a result, it is possible to increase the degree of constant volume of a fuel-air mixture at the time of combustion and hence to increase thermal efficiency of the internal combustion engine.