Abstract: In a network, a controller controls a physical-interconnection selection switch and middle switches so as to dynamically change a network topology according to the state of the network. A traffic analyzer detects how the traffic in the network changes. If there is a change in traffic, the controller controls the physical-interconnection selection switch and the middle switches so as to change the network topology to one suitable for the changed traffic.

Abstract: A drop-type AOTF is used as a configuration for removing from a through signal an optical signal having the same wavelength as that of an optical signal to be added. To the drop-type AOTF, RF signals are input to always select all of wavelengths, and an RF signal is not input for a wavelength desired to be rejected. As a result, the optical signal having the wavelength for which the RF signal is stopped is not selected by the drop-type AOTF, and cannot pass through. Since there is only one RF signal whose input is stopped, a “drawing effect” does not occur, and control of an optical add/drop device is simplified. Additionally, since high-speed switching can be made, and a wavelength to be added can be varied, restrictions are not imposed on a network configuration.

Abstract: A radio-frequency-signal generator generates an RF signal. An optical monitor monitors a first intensity of a reference signal and a second intensity of a drop signal. A reference-frequency determining unit determines, based on the first intensity, a first frequency of an RF signal that causes the AOTF to output the reference signal. A temperature detecting unit detects a temperature of the AOTF. A frequency calculating unit calculates a second frequency of an RF signal that causes the AOTF to output a drop signal of a desired wavelength. A control unit controls the RF-signal generator to generate the RF signal of the second frequency calculated.

Abstract: An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.

Abstract: A radio-frequency-signal generator generates an RF signal. An optical monitor monitors a first intensity of a reference signal and a second intensity of a drop signal. A reference-frequency determining unit determines, based on the first intensity, a first frequency of an RF signal that causes the AOTF to output the reference signal. A temperature detecting unit detects a temperature of the AOTF. A frequency calculating unit calculates a second frequency of an RF signal that causes the AOTF to output a drop signal of a desired wavelength. A control unit controls the RF-signal generator to generate the RF signal of the second frequency calculated.

Abstract: The present invention relates to a control method and device for an optical filter, and a primary object of the present invention is to achieve accurate tracking control of the optical filter. Disclosed herein is a control method for an optical filter including first and second optical filter units cascaded, each having an input and first and second outputs. The first output of the first optical filter unit is connected to the input of the second optical filter unit. First light output from the second output of the first optical filter unit is converted into a first electrical signal having a level corresponding to the power of the first light, and second light output from the second output of the second optical filter unit is converted into a second electrical signal having a level corresponding to the power of the second light. A control signal is generated according to the first and second electrical signals. Then, the first and second optical filter units are controlled according to the control signal.

Abstract: A method of wavelength selection control is disclosed.

Abstract: The present invention provides an information processing system, comprising a plurality of calculation nodes with an optical transmitter, which individually outputs a plurality of optical signals each having a different wavelength, and an optical receiver, which individually receives a plurality of optical signals each having a different wavelength, an optical transmission path connecting a plurality of the calculation nodes to each other, and optical pathway switching unit, lying in the optical transmission path, for transmitting the optical signal to the specific calculation node in accordance with a wavelength of the optical signal output from one of the calculation nodes.

Abstract: An optical network system is disclosed by which flexible wavelength path setting can be performed in accordance with tree-shaped and star-shaped network topology. A central node includes a multiplexing section for multiplexing optical signals transmitted from user nodes and inputted thereto, and a central node side branching section for branching the optical signal multiplexed by the multiplexing section and supplying the branched optical signals to the user nodes. Each of the user nodes includes a transmission section capable of outputting an optical signal to which transmission wavelengths different from those of the other user nodes are set, and a reception section for extracting selected optical wavelength components from the branched light supplied thereto from the central node side branching section and extracting optical signals from the extracted optical wavelength components.

Abstract: A wavelength multiplexing processing apparatus for use with a wavelength division multiplexing system is disclosed which uses a single AWG to achieve reduction in cost, size and loss. The wavelength multiplexing processing apparatus includes a waveguide device wherein a plurality of incoming and outgoing waveguides, a first slab waveguide and a plurality of channel waveguides are formed on a substrate, a mirror array device and a lens device. The plane direction angles of reflecting mirrors which reflect optical signal components incoming thereto are set so that reflected light of an optical signal component incoming from one of the plural incoming and outgoing waveguides may go out from one of the plural incoming and outgoing waveguides.

Abstract: An optical apparatus having a loss compensation capability includes between an input connector 1A and an output connector 1B an input side optical parts 2 including an input monitor, an amplification medium 3, a loss medium 4, and an output side optical parts 5 including an output monitor in this order, and is provided with a control circuit 6 for controlling a gain based on a monitor result of input/output light. The amount of reflection attenuation on all points, on which the light can be reflected on the optical path from the output end of the amplification medium 3 to the output connector 1B, can be smaller than the amount of reflection attenuation on the end face of the output connector 1B.

Abstract: An optical transmission apparatus and method for changing a rise time (tr) and fall time (tf) of a signal light to be transmitted, to reduce wavelength dispersion characteristics and nonlinear effect of a transmission path. A transmitter includes a trtf adjusting circuit capable of adjusting tr and tf of a modulation signal so that the modulation signal is optimized in accordance with reception characteristics. A modulator then modulates a light with this adjusted modulation signal, and the modulated light is then transmitted to a receiver via a transmission path. Therefore, by transmitting the modulated light having changed tr and tf, the influence of wavelength dispersion characteristics and nonlinear effect of the transmission path can be offset, so that the waveform deterioration of signal light after transmission can be reduced.

Abstract: The present invention relates to an optical communication apparatus for detecting the intensity of light in an optical modulator or the intensity of a modulation signal and for controlling the operating point of the optical modulator based on the result of detection. In the optical communication apparatus having such a configuration, the operating point of the optical modulator can be kept stable even when the input light or the modulation signal is temporarily non-existent in the optical communication apparatus.

Abstract: Disclosed herein is a light source device and a wavelength control device therefor. The light source device includes a plurality of laser diodes, a temperature sensor provided in the vicinity of the plurality of laser diodes, a control loop for controlling the temperatures of the plurality of laser diodes according to an output from the temperature sensor to thereby control the oscillation wavelengths of the plurality of laser diodes, and a unit for compensating temperature control conditions for the laser diodes other than a reference laser diode selected from the plurality of laser diodes, according to a change in temperature control condition for the reference laser diode. By the compensation of the temperature control conditions, the oscillation wavelength of each laser diode can be easily stabilized to each wavelength channel of WDM.

Abstract: A drop-type AOTF is used as a configuration for removing from a through signal an optical signal having the same wavelength as that of an optical signal to be added. To the drop-type AOTF, RF signals are input to always select all of wavelengths, and an RF signal is not input for a wavelength desired to be rejected. As a result, the optical signal having the wavelength for which the RF signal is stopped is not selected by the drop-type AOTF, and cannot pass through. Since there is only one RF signal whose input is stopped, a “drawing effect” does not occur, and control of an optical add/drop device is simplified. Additionally, since high-speed switching can be made, and a wavelength to be added can be varied, restrictions are not imposed on a network configuration.

Abstract: The present invention aims at providing a control method and a control apparatus for controlling the operation setting of an optical device with high accuracy, so as to reliably obtain characteristics according to a desired relationship to be set corresponding to a signal light, immediately after the control start.

Abstract: The present invention relates to a light source apparatus. The light source apparatus includes a plurality of optical pulse train generation sections; an optical switch section capable of selectively outputting an optical pulse train to be taken as an optical pulse train for current use; an output light generation section capable of generating continuous light of multiple wavelengths from said optical pulse train output from said optical switch section; and an optical switch control section for controlling said optical switch section to switch an output of said optical pulse train for current use from said optical switch section, in accordance with the states of respective optical pulse trains generated by said plurality of optical pulse train generation sections and without involvement of instantaneous power interruption.

Abstract: The present invention has an object to provide a control method and a control apparatus for a variable wavelength optical filter, which can reliably and stably control drive conditions of the variable wavelength optical filter, independent of the number of wavelengths to be selectively separated in collective.

Abstract: The present invention aims at providing a control method and a control apparatus for controlling the operation setting of an optical device with high accuracy, so as to reliably obtain characteristics according to a desired relationship to be set corresponding to a signal light, immediately after the control start.

Abstract: The invention provides an optical wavelength multiplex transmission method wherein a band in the proximity of a zero dispersion wavelength of an optical fiber is used and optical signals are disposed at efficient channel spacings taking an influence of the band, the wavelength dispersion and the four wave mixing into consideration to realize an optical communication system of an increased capacity which is not influenced by crosstalk by FWM. When optical signals of a plurality of channels having different wavelengths are to be multiplexed and transmitted using an optical fiber, a four wave mixing suppressing guard band of a predetermined bandwidth including the zero-dispersion wavelength ?0 of the optical fiber is set, and signal light waves of the plurality of channels to be multiplexed are arranged on one of the shorter wavelength side and the longer wavelength side outside the guard band.