Abstract: A power transmission chain includes a plurality of links, a plurality of pins, and a plurality of interpieces. By pressing upper and lower edges of the pin into upper and lower edges of a through hole, the pin is connected to the link. The end of the pin which is located at a front end side when the pin is pressed is formed in a shape into which the upper and lower edges of the pin are pressed at the same time.

Abstract: An optical transmission system is provided with a broadband optical transmitter including a broadband light source and a broadband optical modulator, an optical filter, an optical modulator, a transmission path, a wavelength router, and an optical receiver. The broadband optical transmitter outputs a broadband optical signal to the optical filter. The optical filter uses a branch wavelength bandwidth of the wavelength router as a basis for transmittance therethrough, and outputs only an applicable optical signal to the optical amplifier. The wavelength router simultaneously distributes the optical signal coming via the transmission path to each corresponding output port. In optical receivers, the optical signals penetrated through the wavelength router are converted into electrical signals.

Abstract: First and second carrier modulators each modulate a carrier having a different frequency from each other with a baseband input signal. First and second variable wavelength optical modulators each convert the modulated signal into an optical signal having a first or second wavelength. An optical multiplexer multiplexes the optical signals, and sends a multiplexed signal to an optical transmission line. A wavelength separator individually outputs wavelength components of the multiplexed signal. First and second optical receivers each convert these wavelength components into an electrical signal. First and second filters each pass only the signal components of each different frequency. First and second burst demodulators each demodulate the modulated signal. With such a structure, a large-capacity optical communication apparatus which is capable of simultaneously using the same wavelength without requiring wavelength management in optical transmitting circuits can be achieved at a low cost.

Abstract: There provided are transmission and reception apparatuses which can realize performing key distribution and encrypted communication in a simultaneous manner. A transmission apparatus overlaps minute amplitude modulation based on a random number signal on a multi-level signal generated based on information data and key information. A reception apparatus, in addition to data identification, performs, by using 2 threshold values between which a sufficiently larger interval than a modulation amplitude by a random number is provided, 3 kinds of identification for the random number signal: “1”, “0”, and “identification impossible”, sends back information of bits with which the identification has succeeded, and shares the sent bits as a new key. Thus, the common device including the transmission and reception apparatuses can realize performing the key distribution and the encrypted communication in the simultaneous manner.

Abstract: A detector outputs a detection signal indicating amplitude variation of an input frequency-multiplexed signal. An amplitude controller adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal. A modulator modulates the amplitude-adjusted frequency-multiplexed signal to produce a predetermined modulated signal. A second multiplexer multiplexes the modulated signal and the detection signal to produce a multiplexed signal. An optical transmitter converts the multiplexed signal into an optical signal, and then sends it out to an optical transmission path. An optical receiver converts the received optical signal into an electrical signal. A separator separates the modulated and detection signals from the electrical signal. A demodulator demodulates the modulated signal to output the frequency-multiplexed signal. An amplitude adjuster adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal to reproduce the original amplitude variation.

Abstract: An optical packet exchanger is provided which, in a situation where a transmission path for an optical packet is to be switched by using an address signal, prevents the transmittable capacity for the information signal from being decreased, and which facilitates the extraction of the address signal even if the modulation speed for the information signal becomes high. An optical modulation section 102 outputs an optical packet obtained by subjecting output light from a light source 101 to an intensity modulation using an information signal and a phase modulation using an address signal corresponding to a transmission destination for the information, signal. An optical splitter section 301 splits the optical packet received via the optical transmission section 200 into two optical packets. An address reading section 302 reads the address signal from the phase of one of the optical packets output from the optical splitter section 301.

Abstract: This invention discloses an optical burst transmission system in which an optical generator generates Type 1 lightwaves having different wavelengths corresponding to transmission lines and having undergone intensity modulation with obtained data; a broad spectrum optical generator generates, by incorporating Type 2 lightwaves, a Type 3 lightwave using a fewer light emitting devices than the number of the Type 1 lightwaves, each Type 2 lightwaves having a corresponding wavelength apart from Type 1 lightwave's wavelength with an FSR interval and having undergone the intensity modulation with clock signals; an optical multiplexer multiplexes the Type 1 and Type 3 lightwaves to output the combination to each transmission line; and an optical routing unit extracts, from the combination, pairs of one Type 1 lightwave and one Type 2 lightwave having the corresponding wavelength, and guides pairs to each transmission line corresponding to the Type 1 lightwave's wavelength in each pair.

Abstract: A detector outputs a detection signal indicating amplitude variation of an input frequency-multiplexed signal. An amplitude controller adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal. A modulator modulates the amplitude-adjusted frequency-multiplexed signal to produce a predetermined modulated signal. A second multiplexer multiplexes the modulated signal and the detection signal to produce a multiplexed signal. An optical transmitter converts the multiplexed signal into an optical signal, and then sends it out to an optical transmission path. An optical receiver converts the received optical signal into an electrical signal. A separator separates the modulated and detection signals from the electrical signal. A demodulator demodulates the modulated signal to output the frequency-multiplexed signal. An amplitude adjuster adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal to reproduce the original amplitude variation.

Abstract: A transmitting-end device generates a pilot signal with a pilot signal generation section, and transmits a pilot signal to a receiving-end device. At the receiving-end device, a transmission rate modification section detects the transmission band of an optical transmission line based on the amplitude of the pilot signal, and decides a data transmission rate acceptable to the receiving-end device by taking into account the transmission band of the optical transmission line. Based on a maximum data transmission data acceptable to the transmitting-end device and the data transmission rate thus decided, a control section in the receiving-end device arbitrates a data transmission rate between it and the transmitting-end device.

Abstract: A data unit 1010 outputs an information signal to be transmitted in the form of optical packets, as well as wavelength information representing a wavelength of each optical packet. A first modulating signal processing unit 1051 receives an information signal, and inserts an electric signal (“dummy signal”) in any no-data period during which the information signal is absent, and outputs the resultant signal as a modulating signal. The dummy signal has the same amplitude as that of the information signal. A wavelength information processing unit 1021 outputs a wavelength controlling current corresponding to the wavelength information, and in any no-data period, outputs a wavelength controlling current corresponding to a wavelength which is different from the wavelengths represented by the wavelength information. A wavelength-tunable light source 1030 outputs light of a wavelength corresponding to the wavelength controlling current.

Abstract: A detector outputs a detection signal indicating amplitude variation of an input frequency-multiplexed signal. An amplitude controller adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal. A modulator modulates the amplitude-adjusted frequency-multiplexed signal to produce a predetermined modulated signal. A second multiplexer multiplexes the modulated signal and the detection signal to produce a multiplexed signal. An optical transmitter converts the multiplexed signal into an optical signal, and then sends it out to an optical transmission path. An optical receiver converts the received optical signal into an electrical signal. A separator separates the modulated and detection signals from the electrical signal. A demodulator demodulates the modulated signal to output the frequency-multiplexed signal. An amplitude adjuster adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal to reproduce the original amplitude variation.

Abstract: An optical transmission system for optically transmitting at least one data signal includes pulse train generating means for converting each of the at least one data signal respectively to a pulse train, based on at least one encoding pattern that is uniquely predetermined corresponding to the at least one data signal, and outputting the pulse train, optical modulating means for converting the pulse train output from the pulse train generating means to an optically modulated signal and outputting the signal, an optical transmission path for transmitting the optically modulated signal that is output from the optical modulating means, optical detecting means for converting the optically modulated signal transmitted on the optical transmission path to an electrical signal and outputting the signal, and data signal extracting means for obtaining the pulse train from the electrical signal that is output from the optical detecting means based on a decoding pattern that uniquely corresponds to the encoding pattern a

Abstract: In a transmitter (11), a peak detection section (104) detects a peak factor of a frequency division multiplexed signal which is output from a frequency division multiplex section (103). A spurious calculation section (105) instructs a gain adjustment section (106) to adjust the signal level of the frequency division multiplexed signal so that the level of spurious components (e.g., adjacent channel leakage power ratio (ACLR)) is equal to or less than a predetermined level, based on the peak factor.

Abstract: First and second carrier modulators each modulate a carrier having a different frequency from each other with a baseband input signal. First and second variable wavelength optical modulators each convert the modulated signal into an optical signal having a first or second wavelength. An optical multiplexer multiplexes the optical signals, and sends a multiplexed signal to an optical transmission line. A wavelength separator individually outputs wavelength components of the multiplexed signal. First and second optical receivers each convert these wavelength components into an electrical signal. First and second filters each pass only the signal components of each different frequency. First and second burst demodulators each demodulate the modulated signal. With such a structure, a large-capacity optical communication apparatus which is capable of simultaneously using the same wavelength without requiring wavelength management in optical transmitting circuits can be achieved at a low cost.

Abstract: First and second carrier modulators each modulate a carrier having a different frequency from each other with a baseband input signal. First and second variable wavelength optical modulators each convert the modulated signal into an optical signal having a first or second wavelength. An optical multiplexer multiplexes the optical signals, and sends a multiplexed signal to an optical transmission line. A wavelength separator individually outputs wavelength components of the multiplexed signal. First and second optical receivers each convert these wavelength components into an electrical signal. First and second filters each pass only the signal components of each different frequency. First and second burst demodulators each demodulate the modulated signal. With such a structure, a large-capacity optical communication apparatus which is capable of simultaneously using the same wavelength without requiring wavelength management in optical transmitting circuits can be achieved at a low cost.

Abstract: An optical transmission system including an optical transmitting device (2) and an optical receiving device (3). The optical transmitting device (2) includes: a data signal splitting section (11, 12) for splitting information included in the data signal into at least two pieces of information and generating at least two electrical signals having different center frequencies and bands; a frequency multiplexing section (13) for performing frequency multiplexing for the at least two electrical signals; and an electrical-to-optical conversion section (14) for converting the frequency-multiplexed signal to an optical signal and sending it to an optical transmission path.

Abstract: A detector outputs a detection signal indicating amplitude variation of an input frequency-multiplexed signal. An amplitude controller adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal. A modulator modulates the amplitude-adjusted frequency-multiplexed signal to produce a predetermined modulated signal. A second multiplexer multiplexes the modulated signal and the detection signal to produce a multiplexed signal. An optical transmitter converts the multiplexed signal into an optical signal, and then sends it out to an optical transmission path. An optical receiver converts the received optical signal into an electrical signal. A separator separates the modulated and detection signals from the electrical signal. A demodulator demodulates the modulated signal to output the frequency-multiplexed signal. An amplitude adjuster adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal to reproduce the original amplitude variation.

Abstract: A branch portion 101 branches an inputted electrical signal into an in-phase signal and an opposite phase signal which have an opposite relation as to a phase. A first FM laser 104 converts the in-phase signal into an optical frequency-modulated signal (a first optical signal) having a center wavelength ?1 and then outputs the resultant signal. A second FM laser 105 converts the opposite phase signal into an optical frequency-modulated signal (a second signal) having a center wavelength ?2 and then outputs the resultant signal. The two optical signals are combined and then inputted into an optical-electrical converting portion 106. The optical-electrical converting portion 106 subjects the inputted optical signals to optical heterodyne detection by its square-law detection characteristic, and outputs a beat signal between the two optical signals which is a wide-band FM signal at a frequency corresponding to a wavelength difference ??(=|?1??2|) between the first optical signal and the second optical signal.

Abstract: A detector outputs a detection signal indicating amplitude variation of an input frequency-multiplexed signal. An amplitude controller adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal. A modulator modulates the amplitude-adjusted frequency-multiplexed signal to produce a predetermined modulated signal. A second multiplexer multiplexes the modulated signal and the detection signal to produce a multiplexed signal. An optical transmitter converts the multiplexed signal into an optical signal, and then sends it out to an optical transmission path. An optical receiver converts the received optical signal into an electrical signal. A separator separates the modulated and detection signals from the electrical signal. A demodulator demodulates the modulated signal to output the frequency-multiplexed signal. An amplitude adjuster adjusts the amplitude of the frequency-multiplexed signal by referring to the detection signal to reproduce the original amplitude variation.

Abstract: A first transmitting section frequency-multiplexes a data signal and a monitor signal, and then converts the resultant signal to an optical signal for output. A first receiving section converts the optical signal transmitted via a first optical transmission path and a wavelength demultiplexer into an electrical signal, and then extracts the monitor signal. A difference detector compares a monitor signal level with a predetermined reference level, and then outputs wavelength information to a second optical transmission path. Based on the wavelength information transmitted via the second optical transmission path, a first wavelength controller adjusts the wavelength of the optical signal for stabilization at a predetermined wavelength. Thus, it is possible to achieve a wavelength division multiplex transmission system capable of controlling the wavelength of the optical signal at low cost.