Patent application number | Description | Published |
20080199182 | Transmission system and transmission method - A wavelength division multiplexing system according to the present art adjusts the amount of dispersion compensation (the amount of dispersion compensation of an NZ-DSF and a DCF) every all spans on the basis of the time slot when an intensity modulation signal transmitter outputs an intensity modulation signal and the wavelength interval when a wavelength coupler multiplexes a phase modulation signal (output from a phase modulation signal transmitter) and the intensity modulation signal. | 08-21-2008 |
20080266648 | SIGNAL LIGHT MONITORING APPARATUS, OPTICAL AMPLIFICATION APPARATUS AND OPTICAL RECEPTION APPARATUS, AND SIGNAL LIGHT MONITORING METHOD - According to an aspect of an embodiment, an apparatus includes an optical branching unit for branching an input signal light in four directions, a polarization component extraction unit extracting four polarization components having mutually different polarization parameters from lights branched in four directions by the optical branching unit, and a determination unit determining input/non-input of the signal light based on the four polarization components extracted by the polarization component extraction unit. | 10-30-2008 |
20090047028 | QUADRATURE PHASE-SHIFT KEYING MODULATOR AND PHASE SHIFT AMOUNT CONTROLLING METHOD FOR THE SAME - The improved quadrature phase shift keying modulator has a structure such that the average light output power of phase-shift keying modulation light output from the combining unit is changed according to the phase difference between the first and the second optical signal after being combined by means of applying driving signals different in eye crossing percentage by the first modulator and the second modulator, respectively, and has a power monitor monitoring the average light output power of quadrature phase-shift keying modulated light and a phase shift controlling unit which performs feedback control of the phase shift amount in the phase shifting unit based on the average light output power monitored by the power monitor. | 02-19-2009 |
20090097866 | OPTICAL RECEIVING DEVICE AND OPTICAL TRANSMISSION SYSTEM - According to an aspect of an embodiment, an apparatus includes: a wavelength-to-transmission quality characteristic obtaining unit for obtaining a wavelength-to-transmission quality characteristic; a residual dispersion-to-transmission quality characteristic saving unit for saving a residual dispersion-to-transmission quality characteristic; a wavelength-to-residual dispersion characteristic generating unit for generating a wavelength-to-residual dispersion characteristic from a relationship between the wavelengths of the other channels and the residual dispersion based on the wavelength-to-transmission quality characteristic and the residual dispersion-to-transmission quality characteristic; a variable dispersion compensator for providing variable dispersion compensation to another channel,; and a variable dispersion compensation controlling unit for performing setting control on a dispersion compensation amount. | 04-16-2009 |
20090220242 | OPTICAL ADDING AND DROPPING DEVICE AND OPTICAL TRANSMISSION APPARATUS - An optical adding and dropping device includes a drop section including an input port and having a through port and a plurality of drop ports set as output ports, a first multiplexer adapted to multiplex light from the through port and light from a plurality of add ports, and a spectrum foot removing section provided on the input side of the first multiplexer and adapted to remove a foot of a spectrum of light to be inputted from the add ports to the first multiplexer. The optical adding and dropping device can be configured at a low cost while it has adding and dropping functions. | 09-03-2009 |
20090238571 | OPTICAL TRANSMISSION SYSTEM AND METHOD FOR CHROMATIC DISPERSION COMPENSATION - An optical transmission system including an optical transmission path for transmitting WDM signals multiplexed different wavelength optical signals, the WDM signals including different bit rate optical signals or different modulation format optical signals; a repeater arranged in the optical transmission path, the repeater including a chromatic dispersion compensation unit for compensating chromatic dispersion compensation for the WDM signals; and a network management system including processes of determining a dispersion compensation ratio indicating the ratio with respect to the dispersion compensation amount at which the residual dispersion of the WDM signals are zero after transmission via the optical transmission path, on the bases of the mixture ratio of different optical signals included in the WDM signals, and variably setting the dispersion compensation amount for the in-line repeater according to the dispersion compensation ratio. | 09-24-2009 |
20090274469 | Polarization multiplexed optical transmitting and receiving apparatus - In a polarization multiplexed optical transmitting and receiving apparatus, output light from a light source section of a transmission unit is separated in a polarization separating section, and then modulated in first and second modulation sections, and the modulated lights are synthesized in a polarization synthesizing section, and transmitted to an optical transmission line. Then the polarization multiplexed light propagated through the optical transmission line is demodulated in a reception section of a reception unit, and together with this, transmission characteristic information of the reception light is transferred to the transmission unit. The transmission unit that receives the transmission characteristics information controls a delay section that adjusts a delay amount of relative phases of drive signals of the modulation sections, so that the transmission characteristics of the polarization multiplexed light are within an allowable range. As a result, pulse timing between orthogonal polarization components of the polarization multiplexed light can be flexibly changed with a simple configuration. | 11-05-2009 |
20100028003 | WDM optical transmission system and controlling method thereof - In the WDM optical transmission system, when performing a correction of a control target value of the total light intensity per one channel of the WDM light in each node on a transmission path, a correction value calculation section of each node determines the type of its own node, and if it corresponds to a node (for example, OADM node) that demultiplexes the WDM light into individual channels and performs a predetermined processing, performs correction of the control target value of the total light intensity according to a calculation expression with use of a noise cut ratio. The noise cut ratio is defined according to a filtering characteristic for when demultiplexing the WDM light into individual channels, so that the influence due to removal of the noise components distributed across the intermediate region of each channel due to filtering is reflected in the correction processing of the control target value of the total light intensity. | 02-04-2010 |
20100284689 | Input signal detection device - According to an aspect of an embodiment, a signal detector device includes a first monitor unit, a second monitor unit, and a discriminator unit. | 11-11-2010 |
20100322622 | OSNR MONITOR DEVICE AND OSNR MEASUREMENT DEVICE - An OSNR monitor device includes an optical receiver including a delay interferometer which inputs an optical signal in accordance with a given bandwidth and outputs two optical signals and causes the optical signals to interfere with each other and optical detectors which outputs currents in accordance with optical powers of the optical signals output from the interferometer, an optical power monitor configured to obtain the optical powers of the optical signals received by the optical detectors included in the optical receiver, and an OSNR calculator configured to calculate an optical signal-to-noise ratio in accordance with the optical powers obtained from the optical power monitor and the reception bandwidth. | 12-23-2010 |
20110236023 | SIGNAL LIGHT PROCESSING APPARATUS, LIGHT TRANSMISSION APPARATUS, WAVELENGTH SELECTION SWITCH, WAVELENGTH DIVISION MULTIPLEXING TRANSMISSION SYSTEM, AND SIGNAL LIGHT PROCESSING METHOD - A signal light processing apparatus includes a first wavelength selection switch, a dispersion compensator, and a second wavelength selection switch. The first wavelength selection switch divides an input wavelength-multiplexed signal light into signal lights of each wavelength and outputs the signal lights from a first output port or a second output port in accordance with wavelengths of the divided signal lights. The dispersion compensator compensates dispersion compensation on the signal light output from the first output port by the first wavelength selection switch. The second wavelength selection switch combines the signal light on which dispersion compensation is compensated by the dispersion compensator and the signal light output from the second output port by the first wavelength selection switch. | 09-29-2011 |
20110311222 | OSNR MEASURING DEVICE AND OPTICAL COMMUNICATION SYSTEM - An OSNR measuring device n OSNR measuring device includes an input port to which a signal light is given; a wavelength filter which includes a variable passband, and selectively takes out an optical component corresponding to a signal optical wavelength to be measured from the signal light; a wavelength control circuit which controls the passband of the wavelength filter; a delay interferometer which branches a light output from the wavelength filter and delays one of the branched lights with respect to the other branched light and in which the branched lights are made to interfere with each other; a photodetector which detects a power of a delay interference light output; and an OSNR calculation circuit which calculates, based on a bandwidth of a passband of the wavelength filter and the power of the delay interference light, an optical signal to noise ratio of a signal optical wavelength to be measured. | 12-22-2011 |
20120082465 | OPTICAL TRANSMITTING APPARATUS, OPTICAL RECEIVING APPARATUS, AND OPTICAL COMMUNICATION SYSTEM COMPRISING THEM - A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f | 04-05-2012 |
20120106968 | OPTICAL TRANSMISSION APPARATUS - There is provided an optical transmission apparatus including: a transmitter to output an optical signal to be transferred to other optical transmission apparatus; a first dummy light source to generate first dummy light having a wavelength which is not included in an optical signal received from other optical transmission apparatus; a first wavelength-multiplexer to wavelength-multiplex the optical signal received from other optical transmission apparatus, the optical signal output from the transmitter, and an optical signal with a wavelength, of the first dummy light, which is not included in the optical signal received from other optical transmission apparatus and in the optical signal output from the transmitter; and an optical amplifier to amplify an optical signal multiplexed by the first wavelength-multiplexer. | 05-03-2012 |
20120230682 | SIGNAL LIGHT MONITORING APPARATUS, OPTICAL AMPLIFICATION APPARATUS AND OPTICAL RECEPTION APPARATUS, AND SIGNAL LIGHT MONITORING METHOD - According to an aspect of an embodiment, an apparatus includes an optical branching unit for branching an input signal light in four directions, a polarization component extraction unit extracting four polarization components having mutually different polarization parameters from lights branched in four directions by the optical branching unit, and a determination unit determining input/non-input of the signal light based on the four polarization components extracted by the polarization component extraction unit. | 09-13-2012 |