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 |
20090034988 | Control apparatus and control method for optical modulator - An object of the invention is to provide a control system in which the phase shift between drive signals of an optical modulator can be reliably detected and compensated by a simple configuration. To this end, a control apparatus of the invention, for an optical modulator generating a signal light of a CS-RZ modulation system or the like by two LN modulators connected in series, detects the phase shift between drive signals given to the former and latter stage LN modulators, or judges the phase shift between the drive signals based on intensity information of the electric spectrum of the signal light output from the optical modulator, to control the phases of the drive signals so as to minimize the phase shift. As a result, the phase shift between the drive signals can be reliably detected and compensated by an electric circuit with a simple configuration. | 02-05-2009 |
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 |
20090080894 | Chromatic dispersion compensating apparatus - In order to compensate for chromatic dispersion ad dispersion slope over an entire wavelength band of the optical signal, the wavelength band is split into a plurality of bands, and chromatic dispersion compensation is made to make chromatic dispersion in a central wavelength of each of the bands zero. | 03-26-2009 |
20090080901 | Dispersion compensating apparatus and dispersion compensating method - In a dispersion compensating apparatus, a reference identifying unit identifies a reference (X dB down) that makes a penalty lower than a predetermined value in accordance with optical signal information and a reference identifying table, and a VIPA plate temperature adjusting unit adjusts a refractive index of a VIPA plate by modifying a temperature of the VIPA plate so that a transmission center wavelength derived from the reference matches the wavelength defined by an ITU-T Grid. If a dispersion compensation value setting unit performs an optimal residual dispersion value search, the VIPA plate temperature adjusting unit determines if a filtering penalty is lower than a predetermined value in accordance with a penalty management table. If the filtering penalty is lower than the predetermined value, temperature adjustment of the VIPA plate is not performed. | 03-26-2009 |
20090080902 | DISPERSION COMPENSATION CONTROLLING APPARATUS AND METHOD FOR SEARCHING FOR AMOUNT OF DISPERSION CONTROL - In order to enhance dispersion control, the apparatus includes a dispersion controller; a quality index generator generating a quality index representing a quality of an optical signal output from the dispersion controller; and a searching unit searching for an amount of dispersion control applying to the dispersion controller which amount optimizes the quality index, wherein the searching unit includes a splitting-half searching unit roughly searching, in a splitting half method, a range in which dispersion is controllable by the dispersion controller for an amount of dispersion control such that the quality index generated by the quality index generator becomes preferable, and a sweep searching unit thoroughly searching, by sweeping, a limited range based on the amount of dispersion searched by the splitting-half searching unit for an amount of dispersion control that optimizes the quality index generated by the quality index generator. | 03-26-2009 |
20090148166 | Optical Add/Drop Multiplexer - An optical add/drop multiplexer includes a first optical coupler receiving an optical signal including a plurality of multiplexed wavelengths, a wavelength blocker receiving the optical signal from the first optical coupler, and blocking at least one wavelength of the plurality of multiplexed wavelengths, a first wavelength selective switch, having one input port receiving the outputted optical signal from the first optical coupler and a plurality of output ports, demultiplexing a plurality of arbitrarily selected multiplexed wavelengths from the received optical signal, a second wavelength selective switch, having a plurality of input ports, each input port receiving a different optical signal and one output port, multiplexing a plurality of arbitrarily selected wavelength signals on the plurality of input ports, and a second optical coupler receiving the optical signal output from the wavelength blocker and multiplexed wavelength signal from the second wavelength selective switch. | 06-11-2009 |
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 |
20100028007 | Optical transmission apparatus - Where add optical signals have k different bit rates, an add controller is connected to k (02-04-2010 | |
20100135664 | Chromatic dispersion compensating apparatus - In order to compensate for chromatic dispersion ad dispersion slope over an entire wavelength band of the optical signal, the wavelength band is split into a plurality of bands, and chromatic dispersion compensation is made to make chromatic dispersion in a central wavelength of each of the bands zero. | 06-03-2010 |
20100221002 | Optical signal processing apparatus - An OADM in a wavelength division multiplexing transmission system includes a wavelength selection switch that selects a predetermined wavelength from a multiple optical signal obtained by multiplexing a phase modulated signal and an intensity modulated signal and outputs the selected wavelength signal to a predetermined output port. The wavelength selection switch has a different delay for each wavelength of the multiple optical signal. For example, the wavelength selection switch includes a mirror array. Optical paths from the surfaces of mirrors arranged on the mirror array to the diffraction grating are different in the case of adjacent mirrors. | 09-02-2010 |
20100221013 | OPTICAL TRANSMISSION APPARATUS, WAVELENGTH DIVISION MULTIPLEXING OPTICAL COMMUNICATION SYSTEM AND OPTICAL TRANSMISSION METHOD - An optical transmission apparatus for suppressing deterioration of transmission quality due to XPM in a wavelength division multiplexing optical communication system in which an intensity modulation optical signal and a phase modulation optical signal exist in a mixed form. The apparatus has an intensity inversion signal light output section which outputs light having an intensity pattern obtained by inverting intensity changes of the intensity modulation optical signal near a wavelength of the intensity modulation optical signal in arrangement on wavelength axis of optical wavelengths that can be multiplexed as a wavelength division multiplexed signal as intensity inversion signal light, and a wavelength division multiplexed optical signal output unit which wavelength-division-multiplexes the intensity modulation optical signal, the phase modulation optical signal and light from the intensity inversion signal light output section and outputs a wavelength division multiplexed optical signal. | 09-02-2010 |
20100254716 | Control apparatus and control method for optical modulator - An object of the invention is to provide a control system in which the phase shift between drive signals of an optical modulator can be reliably detected and compensated by a simple configuration. To this end, a control apparatus of the invention, for an optical modulator generating a signal light of a CS-RZ modulation system or the like by two LN modulators connected in series, detects the phase shift between drive signals given to the former and latter stage LN modulators, or judges the phase shift between the drive signals based on intensity information of the electric spectrum of the signal light output from the optical modulator, to control the phases of the drive signals so as to minimize the phase shift. As a result, the phase shift between the drive signals can be reliably detected and compensated by an electric circuit with a simple configuration. | 10-07-2010 |
20110038636 | Optical Add/Drop Multiplexer - An optical add/drop multiplexer includes a first optical coupler receiving an optical signal including a plurality of multiplexed wavelengths, a wavelength blocker receiving the optical signal from the first optical coupler, and blocking at least one wavelength of the plurality of multiplexed wavelengths, a first wavelength selective switch, having one input port receiving the outputted optical signal from the first optical coupler and a plurality of output ports, demultiplexing a plurality of arbitrarily selected multiplexed wavelengths from the received optical signal, a second wavelength selective switch, having a plurality of input ports, each input port receiving a different optical signal and one output port, multiplexing a plurality of arbitrarily selected wavelength signals on the plurality of input ports, and a second optical coupler receiving the optical signal output from the wavelength blocker and multiplexed wavelength signal from the second wavelength selective switch. | 02-17-2011 |
20110058820 | Optical transmission system, optical transmission equipment, and chromatic dispersion compensation method - An optical transmission system includes an optical transmission equipment and an optical receiving device. The optical transmission equipment transmits an optical signal from a first adjacent node to a second adjacent node, and includes an optical multiplexing and demultiplexing unit that demultiplexes the optical signal from the first adjacent node into an optical transmission signal to be transmitted to the second adjacent node and an optical demultiplexed signal, and a compensating unit that partially compensates chromatic dispersion in the optical demultiplexed signal. The optical receiving device receives the optical signal from the optical transmission equipment, and includes a converting unit that converts the optical demultiplexed signal the chromatic dispersion of which is partially compensated by the compensating unit into an electric digital signal, and a digital processing unit that compensates chromatic dispersion remaining in the electric digital signal. | 03-10-2011 |
20110176816 | OPTICAL TRANSMISSION APPARATUS - An optical transmission apparatus according to the present invention comprises: a plurality of optical modulating sections serially connected to each other via optical fibers; driving sections corresponding to the optical modulating sections; delay amount varying sections that provide variable delay amounts for modulating signals to be input to the driving sections, to adjust timing between drive signals to be provided for the optical modulating sections; temperature monitoring sections that monitor the temperature of each of the optical fibers and the like; and a delay amount control section that controls the delay amount in each of the delay amount varying sections based on the monitored temperatures. | 07-21-2011 |
20120082454 | OPTICAL NETWORK INTERCONNECT DEVICE - An optical network interconnect device interconnects a first WDM network for transmitting a WDM optical signal with first wavelength spacing and a second WDM network for transmitting a WDM optical signal with second wavelength spacing that is wider than the first wavelength spacing. The optical network interconnect device includes a filter to remove a wavelength component which is not used in the second WDM network from an WDM optical signal transferred from the first WDM network to the second WDM network. | 04-05-2012 |
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 |
20120170928 | OPTICAL TRANSMITTER, OPTICAL TRANSMISSION METHOD, AND WAVELENGTH-SELECTIVE VARIABLE DELAYER - An optical transmitter is provided for transmitting a wavelength multiplexed signal comprising an intensity modulation optical signal and a phase modulation optical signal through a transmission line. The optical transmitter includes a bit time difference given signal generator for generating at least two optical signals having a bit time difference therebetween, from the wavelength multiplexed signal. The optical transmitter further includes a wavelength multiplexed signal output unit to which at least two optical signals are input from the bit time difference given signal generator, and which generates and outputs a wavelength multiplexed signal in which the bit time difference was given between the phase modulation optical signal and the phase modulation optical signal. | 07-05-2012 |
20120188631 | OPTICAL AMPLIFICATION APPARATUS - In an optical amplification apparatus an optical amplifier amplifies an optical signal at set gain. An equalizer changes loss of the amplified optical signal according to wavelengths. A processor controls the equalizer so as to make the equalizer have a loss-wavelength characteristic corresponding to a gain tilt of the optical amplifier which occurs according to the set gain. | 07-26-2012 |
20120237219 | WAVELENGTH SELECTIVE SWITCH AND OPTICAL TRANSMISSION APPARATUS - A wavelength selective switch includes a wavelength dispersing element, a wavelength converging element, multiple transmission control elements, and a controller. The wavelength dispersing element performs wavelength dispersion of input signal light. The transmission control element divides input signal light into wavelength bands within a channel band and transmits or cuts off the divided input signal light. The wavelength converging element converges signal light having respective wavelengths produced from the transmission control elements for output. The controller controls a transmittance of the transmission control element of at least one of the low and high frequency sides in a channel band. The wavelength selective switch sets as a cutoff band at least one of predetermined bands on the low and high frequency sides, narrows a transmission band of the input signal light to be wavelength-multiplexed, deletes an overlapped band of optical spectra, and outputs the transmission signal light, thereby suppressing crosstalk. | 09-20-2012 |
20140369678 | DUAL-POLARIZATION INTERFEROMETRIC OPTICAL SIGNAL-TO-NOISE RATIO MONITOR - The present disclosure includes a method of determining optical signal-to-noise ratio (OSNR) of a signal, comprising separating one polarization component from a plurality of polarization components in an optical signal, selecting one wavelength from a plurality of wavelengths in the optical signal, delaying a first portion of the one polarization component of the one wavelength of the optical signal, shifting a phase of the first portion by a first amount and the first amount plus pi radians, causing the first portion to interfere with a second portion, measuring a power of the interference of the first and second portions, receiving the power of the interference, and comparing the power of the interference when the phase is shifted by the first amount with the interference when the phase is shifted by the first amount plus pi radians to determine OSNR. The present disclosure also includes associated devices. | 12-18-2014 |