摘要:
An OCDM signal generation section generates an encoded optical pulse signal by encoded an optical pulse signal. The encoded optical pulse signal is then inputted to a wavelength disperser and the time waveform of the encoded optical pulse signal is shaped to be outputted as a shaped and encoded optical pulse signal. A WDM signal generation section generates an optical wavelength division multiplexing signal. A OCDM signal extraction section then decodes the OCDM reception signal by using the same code as the time-spreading/wavelength-hopping code for each channel and generates a decoded OCDM reception signal.
摘要:
An object of the present invention is to implement optical multiplexing transmission and reception in which an OCDM channel is added without changing the used wavelength bandwidth of the existing WDM channel or without changing the time slot allocated to the existing OTDM channel. Hence, one of the embodiments of the present invention is constituted as follows. The OCDM signal generation section generates an encoded optical pulse signal by encoding an optical pulse signal. The encoded optical pulse signal is inputted to the wavelength disperser and the time waveform of the encoded optical pulse signal is shaped to be outputted as a shaped and encoded optical pulse signal. The WDM signal generation section generates an optical wavelength division multiplexing signal. The OCDM signal extraction section decodes the OCDM reception signal by using the same code as the time-spreading/wavelength-hopping code for each channel and generates a decoded OCDM reception signal. The shaped and encoded optical pulse signal component that is contained in the decoded OCDM reception signal is restored by the inverse-wavelength disperser and a reproduced optical pulse signal is generated. Only the autocorrelation waveform component of the optical pulse signal constituting the OCDM transmission signal is extracted from the reproduced optical pulse signal by the first threshold value judgment section. In the WDM signal extraction section, the second threshold value judgment section extracts the WDM signal of each channel from the WDM reception signal.
摘要:
According to the present invention, a code selection device wherein, an unused spreading code, or one of a plurality of unused spreading codes, is selected for allocation to a new communication channel, comprises: a dummy spreading signal generator for despreading dummy original data by using the unused spreading code or codes available for employment, and generating dummy spreading signals; a superimposing unit for superimposing the dummy spreading signals and received signals and forming pseudo superimposed signals; a despreading unit for despreading the pseudo superimposed signals by using the unused spreading codes related to the corresponding pseudo superimposed signals, and the spreading codes already used for communication channels that previously have been established; and a spreading code selector for selecting an unused spreading code based on data for the communication channels reproduced for the pseudo superimposed signals and the reproduced dummy original data. With this configuration, a method can be provided whereby, in accordance with the usage condition of a network, a code sequence having a preferable correlation property can be selected, from among a number of code sequences that are generated, and allocated to a communication channel.
摘要:
An OCDM communication system and a method for correcting failure of the same are provided. In the system, encoders and decoders are provided respectively for channels. Each encoder, including an SSFBG, encodes an optical signal using a code value determined according to distance between adjacent unit fiber Bragg gratings in the SFFBG. Each decoder, including an SFFBG, generates a received optical signal by decoding the encoded signal using a code value determined in the same manner. A set temperature of each encoder and decoder is calculated and a corresponding control signal is generated based on average power and error rate detection signals of each received optical signal. The temperature of each encoder or decoder is individually adjusted according to the control signal, which makes equal the code values of an encoder and decoder of a channel in which average power of a received signal has changed or error rate thereof is excessive.
摘要:
An object of the present invention is to provide an OCDM transceiver with which the reduction amount of the intensity of the correlation waveform signal is smaller than that of a conventional device of the same type in the decoding step that comprises a time gate processing step. Hence, in the OCDM transceiver of the present invention that comprises an encoding portion and a decoding portion, the decoding portion is constituted comprising a decoder, clock extractor, and time gate. The decoder decodes an encoded optical pulse signal and separates the encoded optical pulse signal into a clock signal extraction signal and an optical pulse signal playback signal. The clock extractor extracts a clock signal from the clock signal extraction signal. Further, the time gate removes only the auto-correlation waveform component from the optical pulse signal playback signal. The auto-correlation waveform component is converted to an electrical signal by means of an optical receiver and generated as a reception signal.
摘要:
An optical modulating circuit realizing a PPM is constituted by circuit parts having a frequency band equal to a data rate to provide a technique which increase the data rate. A first light source generates a first single wavelength signal serving as a continuous light having a first wavelength λ1 as a wavelength of a carrier wave. A second light source generates a second single wavelength signal serving as a continuous light having a second wavelength λ2 different from λ1 as a wavelength of a carrier wave. For the first single wavelength signal and the second single wavelength signal, according to a transmission electric signal having information 0 or 1, an optical switch outputs a first single wavelength signal as an input optical signal when the information is 0. On the other hand, when the information is 1, the optical switch outputs the second single wavelength signal as an input optical signal. An optical modulator generates an optical pulse signal obtained by arranging optical pulses having λ1 or λ2 as a wavelength of a carrier wave at predetermined time intervals from the input optical signal. A delaying unit delays the optical pulse having the wavelength λ1 and the optical pulse having the wavelength λ2 by different delay time Δt to obtain a PPM signal.
摘要:
An object of the present invention is to provide an OCDM transceiver with which the reduction amount of the intensity of the correlation waveform signal is smaller than that of a conventional device of the same type in the decoding step that comprises a time gate processing step. Hence, in the OCDM transceiver of the present invention that comprises an encoding portion and a decoding portion, the decoding portion is constituted comprising a decoder, clock extractor, and time gate. The decoder decodes an encoded optical pulse signal and separates the encoded optical pulse signal into a clock signal extraction signal and an optical pulse signal playback signal. The clock extractor extracts a clock signal from the clock signal extraction signal. Further, the time gate removes only the auto-correlation waveform component from the optical pulse signal playback signal. The auto-correlation waveform component is converted to an electrical signal by means of an optical receiver and generated as a reception signal.
摘要:
According to the present invention, a code selection device wherein, an unused spreading code, or one of a plurality of unused spreading codes, is selected for allocation to a new communication channel, comprises: a dummy spreading signal generator for despreading dummy original data by using the unused spreading code or codes available for employment, and generating dummy spreading signals; a superimposing unit for superimposing the dummy spreading signals and received signals and forming pseudo superimposed signals; a despreading unit for despreading the pseudo superimposed signals by using the unused spreading codes related to the corresponding pseudo superimposed signals, and the spreading codes already used for communication channels that previously have been established; and a spreading code selector for selecting an unused spreading code based on data for the communication channels reproduced for the pseudo superimposed signals and the reproduced dummy original data. With this configuration, a method can be provided whereby, in accordance with the usage condition of a network, a code sequence having a preferable correlation property can be selected, from among a number of code sequences that are generated, and allocated to a communication channel.
摘要:
An object of the present invention is to provide an OCDM transceiver with which the reduction amount of the intensity of the correlation waveform signal is smaller than that of a conventional device of the same type in the decoding step that comprises a time gate processing step. Hence, in the OCDM transceiver of the present invention that comprises an encoding portion and a decoding portion, the decoding portion is constituted comprising a decoder, clock extractor, and time gate. The decoder decodes an encoded optical pulse signal and separates the encoded optical pulse signal into a clock signal extraction signal and an optical pulse signal playback signal. The clock extractor extracts a clock signal from the clock signal extraction signal. Further, the time gate removes only the auto-correlation waveform component from the optical pulse signal playback signal. The auto-correlation waveform component is converted to an electrical signal by means of an optical receiver and generated as a reception signal.
摘要:
An OCDM signal generation section generates an encoded optical pulse signal by encoded an optical pulse signal. The encoded optical pulse signal is then inputted to a wavelength disperser and the time waveform of the encoded optical pulse signal is shaped to be outputted as a shaped and encoded optical pulse signal. A WDM signal generation section generates an optical wavelength division multiplexing signal. A OCDM signal extraction section then decodes the OCDM reception signal by using the same code as the time-spreading/wavelength-hopping code for each channel and generates a decoded OCDM reception signal.