Abstract: An apparatus comprising an optical modulator modulating a light in accordance with a modulation signal and an operating point of the optical modulator, to thereby output a modulated optical signal; and a controller controlling the operating point in accordance with a branched portion of the modulated optical signal and a detected intensity of the modulation signal so that the operating point is kept stable when the detected intensity falls below a predetermined value.

Abstract: An optical transmitting apparatus includes a modulating unit that branches an input light and performs independent phase modulation to branched optical signals of arms, a phase adjusting unit that changes a phase difference between the optical signals of respective arms according to a control signal, a combining unit that combines modulated lights having the phase difference, an acquiring unit that acquires a positive-phase signal and a negative-phase signal from the combining unit, a subtracting unit that obtains a difference between the positive-phase signal and the negative-phase signal acquired by the acquiring unit, a detecting unit detecting a power of a differential signal from subtraction by the subtracting unit, and a control unit that changes the control signal according to signal component intensity detected by the detecting unit.

Abstract: An apparatus comprising an optical modulator modulating a light in accordance with a modulation signal and an operating point of the optical modulator, to thereby output a modulated optical signal; and a controller controlling the operating point in accordance with a branched portion of the modulated optical signal and a detected intensity of the modulation signal so that the operating point is kept stable when the detected intensity falls below a predetermined value.

Abstract: Signal light with a specific wavelength is transmitted and extracted from signal light multiplexed by a WDM method, and a light detection unit detects the signal light detected by an optical tunable filter, whose wavelength transmission characteristic varies depending on a control signal. An operation circuit generates information for designating a control signal needed to enable the optical tunable filter to extract signal light with a designated wavelength, based on the detected results of two segments of signal light located at each edge of a wavelength band obtained by shifting the wavelength transmission characteristic of the optical tunable filter from outside the wavelength band including all segments of the entire WDM signal. A driving circuit generates a control signal according to the designation information.

Abstract: An optical device module includes an optical device, a soaking unit fixed to one surface of the optical device, a heating/cooling unit fixed to one surface of the soaking unit, a heat-insulating unit fixed to one surface of the heating/cooling unit, and a package that houses the optical device, the soaking unit, the heating/cooling unit, and the heat-insulating unit and to which the heat-insulating unit is fixed. The heating/cooling unit heats the optical device using self-generated heat or cools the optical device via the soaking unit.

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: A polarization controller is configured to comprise polarization state monitoring section for monitoring polarization states of input light and output light of a variable polarization light element; and a control section, when the positions on a Poincare sphere expressing each of the polarization states monitored by the polarization state monitoring section are at the positions being symmetric or approximately symmetric for the equator of the Poincare sphere, for rotating the Poincare sphere by ? by using the earth axis of the Poincare sphere as a rotation axis by changing the azimuth of the optical axis of the variable polarization light element, and also for inverting the changing direction of the phase shift amount. By this, arbitrary and endless control of polarization light can be realized by a phase shift amount being less than the wavelength ? of the input light.

Abstract: According to an aspect of an embodiment, an optical modulation device includes a Mach-Zehnder modulator and a controller. The Mach-Zehnder modulator is supplied a drive signal and a bias voltage. The Mach-Zehnder modulator modulates inputted light on the bases of the drive signal and the bias voltage. The drive signal selectively is superimposes a predetermined frequency signal. The bias voltage selectively is superimposes the predetermined frequency signal. The controller selects a superimposing target which is the drive signal or the bias voltage so as to change modulation formats.

Abstract: The disclosed optical transmitter and control method include performing phase modulation of a light propagating through a corresponding optical path in accordance with a data signal, supplying bias voltages for regulating an operating point of each of phase modulation performed, imparting a predetermined phase difference, supplying bias voltages for phase difference regulation and coupling lights output from the corresponding optical paths. The optical transmitter includes superimposing a pilot signal on either one of bias voltages where the pilot signal has a frequency lower than a frequency of a bit rate of the data signal, and performing a feedback control in accordance with a result of monitoring.

Abstract: An optical transmission device improved in quality and reliability of OADM function and permitting configuration of highly-flexible, economical OADM networks. A wavelength tunable filter variably selects a wavelength according to a control frequency. A filter controller applies the control frequency to the filter while scanning wavelength over an entire signal bandwidth, to detect, from a reference wavelength monitor signal supplied thereto, a reference control frequency which permits the filter to select a reference wavelength and according to which wavelength is matched. On receiving a wavelength selection request, the controller obtains a target control frequency from the reference control frequency and the position of a target wavelength relative to the reference wavelength, and applies the obtained frequency to the filter. A reference wavelength filter transmits the reference wavelength therethrough. A light-receiving element monitors the transmitted reference wavelength to generate the monitor signal.

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: The present invention is a miniaturized differential M phase-shift modulator (M=2n: n is 2 or more) in which a plurality of Mach-Zehnder type light modulators each adapted to output a DPSK-modulated signal light by applying a driving voltage signal are arranged in parallel and that comprises a multiplexing waveguide adapted to output a DMPSK-modulated light by multiplexing outputs of the plurality of the Mach-Zehnder type light modulators, wherein a phase-shift voltage to produce a phase shift difference of substantially 2?/M for a plurality of the signal lights multiplexed by the multiplexing waveguide is applied to the plurality of the Mach-Zehnder type light modulators together with the driving voltage signal.

Abstract: A wavelength stabilizing filter has a wavelength transmission characteristic curve that has its peak in a wavelength located between a first continuous set band and a second continuous set band longer in wavelength than the first set band, and that linearly drops from the peak toward the shorter wavelength side than the first set band and also toward the longer wavelength side longer than the second set band. A control unit generates a control signal needed to enable an optical tunable filter to extract signal light with a predetermined wavelength from an inputted WDM signal, based on light transmitted through the wavelength stabilizing filter.

Abstract: An apparatus comprising an optical modulator modulating a light in accordance with a modulation signal and an operating point of the optical modulator, to thereby output a modulated optical signal; and a controller controlling the operating point in accordance with a branched portion of the modulated optical signal and a detected intensity of the modulation signal so that the operating point is kept stable when the detected intensity falls below a predetermined value.

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: A method of wavelength selection control is disclosed.

Abstract: An optical wiring switching unit includes a first connection interface. A packet switch includes a second connection interface. A resource includes a third connection interface, and is formed with at least one of a server and a storage device. A control device controls the optical wiring switching unit to perform a switching of connection between the connection interfaces. The packet switch and the resource are connected to the optical wiring switching unit via the connection interfaces. A network is configured by connecting the packet switch and the resource with a control of the optical wiring switching unit.

Abstract: An optical power information receiving unit receives optical power information transmitted from a power monitor. When it is judged that a new IT apparatus is connected to an optical switch, an optical switch control unit controls the optical switch to connect the IT apparatus and an optical switch control device. A control device port setting unit changes an IP address of an apparatus information acquiring port based on a control device setting address of an address information storing unit. An apparatus information acquiring unit acquires an IP address of the IT apparatus.

Abstract: The optical circuit is attachable to a ring system dedicated node apparatus, which performs add/drop on an optical signal received from a first network and transmits to a second network, so as to convert into a linear system dedicated node apparatus that performs add/drop on an optical signal received from the first or second network and transmit to the second or first network. The optical circuit includes an optical filter having a characteristic of reflecting an optical signal band supplied from the second network and transmitting an optical signal band supplied from the first network, and transmitting an occupied band of an add light in the ring system dedicated node apparatus to which the own circuit is attached at a predetermined transmission rate and reflecting the reminder. The ring system dedicated node apparatus is used in common with a part of the linear system dedicated node apparatus.

Abstract: Before wiring of a physical wiring changing-over switch is switched, a communication suspension instructing unit in a controller sends a signal to instruct IT devices connected to the physical wiring changing-over switch to suspend communications for a certain period of time and hold the communication bit strings to be transmitted in a temporary storage area. The signal is sent via an exclusive control line between the controller and the IT devices.