Patent application number | Description | Published |
20080205888 | Semiconductor optical amplifier type gate switch drive circuit, semiconductor optical amplifier type gate switching drive, and optical cross connect - A drive circuit is provided for a semiconductor optical amplifier type gate switch includes a first transmission path and a second transmission path. The first transmission path includes a common first sub-path between a signal source and a first node; and an individual second sub-path for each of a plurality of operational amplifiers between the first node and a corresponding one of the operational amplifiers. The second transmission path includes an individual third sub-path between each of the operational amplifiers and a second node; and a common fourth sub-path between the second node and the semiconductor optical amplifier type gate switches. Transmission delay times of all the individual second sub-paths are equal, and transmission delay times of all the individual third sub-paths are equal. | 08-28-2008 |
20080239472 | Semiconductor optical amplification module, optical matrix switching device, and drive circuit - A semiconductor optical amplification module that can suppress ringing without increasing power consumption or circuit size or inhibiting high-speed operation. A semiconductor optical amplifier outputs an optical signal inputted according to driving current outputted from a drive circuit. A diode is connected in parallel with the semiconductor optical amplifier. As a result, it becomes possible to suppress ringing without connecting a large resistor to the drive circuit. | 10-02-2008 |
20090003827 | Optical switching device - An optical switching device the size and costs of which are reduced by decreasing the number of switching elements and which can flexibly accommodate the expansion of the number of ports. An optical demultiplexing section has 2 | 01-01-2009 |
20090058534 | Non-inverting amplifier circuit and optical switch driver circuit - A non-inverting amplifier circuit is disclosed that includes an operational amplifier and a preemphasis circuit connected between the operational amplifier and a signal source. The preemphasis circuit is configured to compensate for the internal delay of a load connected to the output of the operational amplifier by emphasizing a high-frequency component of a signal fed from the signal source. | 03-05-2009 |
20090060506 | OPTICAL PACKET SWITCHING APPARATUS AND METHOD THEREFOR - An optical switch section that switches the path of an optical packet transmitted thereto and outputs the optical packet, and a control section that generates multiple switch control signals in accordance with the destination of an optical packet transmitted thereto, transmits the multiple control signals to the optical switch section through multiple signal transmission lines and controls the ON/OFF states of multiple optical switches are included, and delay measuring means for measuring a difference in delay time among the multiple signal transmission lines is provided. In this case, the control section adjusts the transmission times of the multiple switch control signals such that the difference in delay time measured by the delay measuring means can be cancelled and that the multiple switch control signals transmitted through the multiple signal transmission lines can arrive at the multiple optical switches simultaneously and transmits the multiple switch control signals. | 03-05-2009 |
20090185804 | Optical access network system - In an optical access network system in which a relay station receives a wavelength multiplexed and time-division multiplexed optical signal (WDM optical signal) from an optical network, and the relay station transmits optical signals having specified wavelengths to subscriber units, the relay station demultiplexes the WDM optical signal into a plurality of groups with one group having a plurality of optical signals having a fixed wavelength interval between signals, then divides the optical signals of each group into k branches (k is the number of subscriber units) and inputs the signals to optical switches, and by turning ON/OFF the optical switches such that they are spaced in time, inputs the branched optical signals to the respective specified subscribers units. | 07-23-2009 |
20090196607 | OPTICAL PACKET SWITCHING APPARATUS AND OPTICAL PACKET SWITCHING METHOD - An apparatus has a plurality of transmitters for transmitting optical packet signals having wavelengths; a multiplexer for multiplexing the optical packet signals transmitted by the plurality of transmitters; a packet scheduler controlling a timing at which each of the transmitters transmits the optical packet signal; and an assister for controlling power of assist light in accordance with a signal from the packet scheduler and causing the assist light to be wavelength-multiplexed with the wavelength multiplexed light such that a total sum of power of the wavelength multiplexed light and the power of the assist light is held constant under a predetermined condition. | 08-06-2009 |
20090237127 | OPTICAL-SWITCH DRIVE CIRCUIT AND METHOD THEREOF - An optical-switch drive circuit including a driver unit that generates, in response to a control signal, an on/off signal for driving a semiconductor optical amplifier gate switch, and a buffer unit having a high input impedance and connected between an output terminal outputting the on/off signal and the semiconductor optical amplifier gate switch. In the optical-switch drive circuit the buffer unit may include a high-resistance voltage divider that is connected with the output terminal, and an operational amplifier that buffers, and provides to the semiconductor optical amplifier gate switch, a divided voltage of the voltage divider. | 09-24-2009 |
20090297147 | Drive circuit and optical switch - A drive circuit includes a first transistor that is controlled to be in on or off state in response to a control signal, and outputs, in on state, a positive current which is input from a first operational amplifier connected with a drain of the first transistor to a semiconductor optical amplifier; and a second transistor that is connected with a source of the first transistor, and is in inverse on or off state to the state of the first transistor. The drive circuit also includes a negative voltage circuit that is connected to a source of the second transistor, and outputs, when the second transistor is in on state, a negative current to the semiconductor optical amplifier. | 12-03-2009 |
20090297162 | Optical communication base station, optical signal conversion apparatus, and optical signal conversion method - An optical communication base station which receives an upstream optical signal having an upstream bit rate specific to each one of a plurality of lower order communication units from a corresponding one of the plurality of lower order communication units, and which transmits a downstream optical signal having a downstream bit rate specific to each one of the plurality of lower order communication units to a designated one of the plurality of lower order communication units, includes; a first optical signal conversion unit which changes the bit rate of the upstream optical signal and thereby converts the upstream optical signal into a fixed bit-rate inter-station optical signal; and a second optical signal conversion unit which converts the inter-station optical signal into the downstream optical signal by changing the bit rate of the inter-station optical signal according to the designated one of the plurality of lower order communication units. | 12-03-2009 |
20100027992 | OPTICAL PACKET SWITCHING APPARATUS - An optical packet switching apparatus includes plural optical switches, an optical switching section that switches a path of an optical packet transmitted thereto according to the switch control signal to output the optical packet, and a control section that takes out a header portion representing a destination of the optical packet transmitted, photoelectrically converts the header to generate the switch control signal according to the destination to transmit the switch control signal to the optical switching section and controls the optical switch. The apparatus further includes a light monitor section that monitors a light quantity level of the optical packet transmitted and a light quantity level of the optical packet to be sent out, and an abnormality recognizing section that recognizes an effective timing of monitoring of the light quantity levels based on the switching control signal, and recognizes an abnormality based on the light quantity levels at the timing. | 02-04-2010 |
20100123945 | WAVEFORM CONTROLLER, RESPONSIVE ELEMENT MODULE, OPTICAL SWITCH APPARATUS, RESPONSIVE ELEMENT AND OPTICAL SWITCH APPARATUS CONTROL METHOD - A waveform controller includes a monitor configured to monitor a waveform of an output pulse obtained by the response of a responsive element to a driving signal supplied thereto and a driving waveform shaper configured to shape a waveform of the driving signal based on a monitoring result obtained by the monitor. | 05-20-2010 |
20100266293 | RELAY APPARATUS, SIGNAL PROCESSING APPARATUS AND OPTICAL COMMUNICATION SYSTEM - A relay apparatus including: a first interface | 10-21-2010 |
20110006124 | TEMPERATURE CONTROL METHOD, TEMPERATURE CONTROL APPARATUS, AND OPTICAL DEVICE - A temperature control apparatus controlling the temperature of an optical element that is driven in response to a drive current that is applied, the temperature control apparatus including: a temperature controller that changes the temperature of the optical element; and a controller that controls current to the temperature controller, wherein the controller determines a time from when an amount of heat from the temperature controller has been generated by the current control until the amount of heat reaches the optical element and controls the current to the temperature controller the determined time before the drive current is applied to the optical element. | 01-13-2011 |
20110050293 | Driving circuit of optical gate switch - A driving circuit of a semiconductor optical amplifier type gate switch constituting a matrix optical switch is provided with an operation amplifier into which a driving signal is input and from which a current corresponding to the driving signal is output, an inductance element provided at an output terminal of the operation amplifier, and a circuit composed of a diode element and a resistor element connected in parallel and provided between the inductance element and the semiconductor optical amplifier. | 03-03-2011 |
20110116798 | OPTICAL COMMUNICATION NETWORK AND SUPERVISORY CONTROL DEVICE - An optical communication network includes a plurality of optical transmission devices, a communication path, an optical repeater, and a supervisory controller that includes a supervisory control information sender which is installed on at least one of one of the optical transmission devices and the optical repeater and controls a drive signal supplied to a semiconductor optical amplifier that amplifies and outputs input signal light onto the communication path on the basis of the supervisory control information, and a supervisory control information receiver that receives the light which has been output from a semiconductor optical amplifier and transmitted through the communication path, converts the received light to an electric signal and identifies the supervisory control information on the basis of an intensity-modulated component of the total power of the electric signal in at least the other of one of the optical transmission devices and the optical repeater. | 05-19-2011 |
20110254608 | LEVEL CONTROL CIRCUIT, LEVEL CONTROL METHOD, AND LEVEL CONTROL SYSTEM - A level control circuit that generates output signal for level control includes: a control information storage that stores control information corresponding to a signal level, a control information circuit that outputs the output signal for level control corresponding to the signal level of a first input signal based on the control information stored in the control information storage; and an information update circuit that updates the control information of the control information storage according to the signal level of a second input signal. | 10-20-2011 |
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 |
20120257272 | OPTICAL AMPLIFICATION APPARATUS - An optical amplification apparatus includes a front-stage semiconductor optical amplifier which amplifies an input light and a rear-stage semiconductor optical amplifier which amplifies an amplified light outputted from the front-stage semiconductor optical amplifier. The front-stage semiconductor optical amplifier exercises auto level control of an output light by exercising variable control of driving current which flows according to applied voltage higher than light emitting threshold voltage of an internal optical amplification element. The rear-stage semiconductor optical amplifier performs gate switching of a transmitted light by exercising switching control of driving current. By doing so, distortion of a waveform is controlled and optical communication quality can be improved. | 10-11-2012 |
20120293228 | LEVEL CONTROL CIRCUIT, LEVEL CONTROL METHOD, AND LEVEL CONTROL SYSTEM - A level control circuit that generates output signal for level control includes: a control information storage that stores control information corresponding to a signal level, a control information circuit that outputs the output signal for level control corresponding to the signal level of a first input signal based on the control information stored in the control information storage; and an information update circuit that updates the control information of the control information storage according to the signal level of a second input signal. | 11-22-2012 |
20120315038 | OPTICAL ACCESS NETWORK SYSTEM - In an optical access network system in which a relay station receives a wavelength multiplexed and time-division multiplexed optical signal (WDM optical signal) from an optical network, and the relay station transmits optical signals having specified wavelengths to subscriber units, the relay station demultiplexes the WDM optical signal into a plurality of groups with one group having a plurality of optical signals having a fixed wavelength interval between signals, then divides the optical signals of each group into k branches (k is the number of subscriber units) and inputs the signals to optical switches, and by turning ON/OFF the optical switches such that they are spaced in time, inputs the branched optical signals to the respective specified subscribers units. | 12-13-2012 |
20130266320 | OPTICAL TRANSMISSION SYSTEM - An optical transmission system includes: multiplex transmitting devices, each configured to modulate, with an optical carrier, a data signal modulated into light by an optical modulator in a non-linear optical medium arranged on a transmission path so as to multiplex the data signal into the optical carrier, the data signal having a frequency different in each of the multiplex transmitting devices; a receiving device configured to execute optical-to-electrical conversion on the optical carrier received from the transmission path so as to execute reception process of the data signals multiplexed by the multiplex transmitting devices; and a management device configured to specify a frequency band to be used, based on a modulation band of each of the optical modulators, and manage assignment of the frequency of each of the data signals within the frequency band to be used so as to avoid an effect of harmonics generated upon the optical-to-electrical conversion. | 10-10-2013 |
20140064732 | APPARATUS AND METHOD FOR RECEIVING OPTICAL SIGNAL, AND OPTICAL FREQUENCY-DIVISION-MULTIPLEXING TRANSMISSION SYSTEM - An optical signal receiving apparatus includes: a chromatic dispersion medium having an amount of chromatic dispersion which is determined according to a frequency of the sub-carrier modulation signals so as to receive the sub-carrier modulation signals, a photodetector configured to convert the carrier optical signal that has passed through the chromatic dispersion medium, into electrical signals, and a signal receiving unit configured to receive an electrical signal selected from the electrical signals obtained by the photodetector. | 03-06-2014 |
20140078579 | OPTICAL OUTPUT LEVEL CONTROL APPARATUS - An optical output level control apparatus includes a detector configured to detect power of an input optical signal; an amplifier configured to amplify the input optical signal; a memory configured to store data that define a first curved line representing a relationship between the input power and a drive voltage of the amplifier for obtaining a first output level and data that defines a second curved line representing a relationship between the input power and the drive voltage of the amplifier for obtaining a second output level; a generator configured to correct at least one of the first and second curved lines and generate a target curved line representing a relationship between input power and a drive voltage of the amplifier for obtaining a target output level through interpolation based on the first and second curved lines at least one of which is corrected. | 03-20-2014 |
20140099115 | TRANSMITTING APPARATUS, RECEIVING APPARATUS, OPTICAL FREQUENCY DIVISION MULTIPLEX TRANSMISSION SYSTEM, AND OPTICAL SIGNAL COMMUNICATION METHOD - A transmitting apparatus is used in an electrical frequency division multiplex transmission system including nodes that are on an optical transmission path and that respectively frequency-multiplex a sub-carrier of a unique frequency and a carrier wave to transmit information to a receiving apparatus on the optical transmission path. The transmitting apparatus is disposed in each node and includes a determining unit that receives an input of information concerning unused sub-carriers of a transmission signal in the optical transmission path and determines transmission of the information to the receiving apparatus using an unused sub-carrier; an electrical frequency division multiplex transmission unit that using a frequency of the unused sub-carrier determined by the determining unit, modulates the input information to be transmitted to the receiving apparatus; and a coupling unit that adds to the transmission signal in the optical transmission path, a modulated modulation signal. | 04-10-2014 |