Abstract: A brushless motor device switches between a 120-degree energization method and a 180-degree energization method of advancing an electrical angle by 30 degrees to drive a brushless motor 1 according to the result of a comparison between the rotational speed of the brushless motor 1 and a predetermined threshold.

Abstract: 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.

Abstract: A hydrogen permeable module includes a hydrogen permeable membrane that permeates hydrogen, an outer peripheral part of the hydrogen permeable membrane being restricted, an inside of the outer peripheral part of the hydrogen permeable membrane being not restricted. The hydrogen permeable module permeates the hydrogen by constantly keeping a pressure of a primary side to a pressure that is equal to or more than a pressure of a secondary side. The inside of the outer peripheral part of the hydrogen permeable membrane is not restricted so as to be capable of expanding to the secondary side.

Abstract: An optical communication apparatus for controlling the operating point of an optical modulation unit appropriately. An adding unit adds a bias voltage and a pilot signal. An optical modulation unit modulates light by an electrical signal, performs further modulation by a signal from the adding unit, and outputs an optical signal. A monitor unit monitors the level of the optical signal and outputs a monitor signal. A reference signal output unit outputs a reference in phase with the pilot signal contained in the monitor signal. A synchronous pilot-signal detection unit performs synchronous detection of the monitor signal by using the reference. A synchronous noise detection unit extracts noise from the monitor signal and performs synchronous detection of the noise by using the reference. A control signal output unit subtracts the synchronous detection value of the noise from that of the monitor signal, and outputs a control signal.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A tape cartridge has a reel having an external peripheral surface and a tape wound around the external peripheral surface of the reel. The peripheral surface has a shallow recess defined therein and extending in a peripheral direction of the reel. The recess is extended in a direction opposite a tape winding direction from a first point to a second point away from the first point. The recess is defined by an end wall extending inwardly from the first point to a third point away from the first point and a height substantially the same as a thickness of the tape. The recess also has a bottom wall extending peripherally from the third point to the second point and having a depth decreasing in proportion to a distance from the third point toward the second point. The portion of the tape is positioned in the recess so that the end wall abuts or opposes the end portion of the tape.

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: An AOTF control apparatus, which applies an RF signal to an AOTF to allow a selected light to pass through the AOTF, includes: a first calculating unit calculating a relationship between a frequency of the RF signal and a wavelength of the selected light based on a frequency of the RF signal that allows a reference light to pass through the AOTF; and a second calculating unit calculating a relationship between a power of the RF signal and an attenuation amount of the selected light based on an input/output power of the reference signal at the input/output of the AOTF.

Abstract: A control system of a multichannel optical switch suppressing the generation of a leakage current in a multichannel, highly integrated EO-SW to enable stable operation, that is, a control system of a multichannel optical switch using devices having an EO effect wherein an electrode voltage application device applies voltage for switching optical switch devices based on switching data when judging that an elapsed time from when the switching data has started to be output from a path switching instruction device is shorter than a predetermined counted time threshold and the electrode voltage application device applies voltage for switching based on the switching data only when a switching judgment processing device judges that predetermined switching conditions have been met when judging that the elapsed time has been exceeded and does not apply voltage for switching to the switch devices and sends a switching failure notice to a path switching instruction device from the switching judgment processing device wh

Abstract: A method of wavelength selection control is disclosed.

Abstract: 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.

Abstract: An optical communication apparatus for controlling the operating point of an optical modulation unit appropriately. An adding unit adds a bias voltage and a pilot signal. An optical modulation unit modulates light by an electrical signal, performs further modulation by a signal from the adding unit, and outputs an optical signal. A monitor unit monitors the level of the optical signal and outputs a monitor signal. A reference signal output unit outputs a reference in phase with the pilot signal contained in the monitor signal. A synchronous pilot-signal detection unit performs synchronous detection of the monitor signal by using the reference. A synchronous noise detection unit extracts noise from the monitor signal and performs synchronous detection of the noise by using the reference. A control signal output unit subtracts the synchronous detection value of the noise from that of the monitor signal, and outputs a control signal.

Abstract: An AOTF control apparatus, which applies an RF signal to an AOTF to allow a selected light to pass through the AOTF, includes: a first calculating unit calculating a relationship between a frequency of the RF signal and a wavelength of the selected light based on a frequency of the RF signal that allows a reference light to pass through the AOTF; and a second calculating unit calculating a relationship between a power of the RF signal and an attenuation amount of the selected light based on an input/output power of the reference signal at the input/output of the AOTF.

Abstract: A response-time storing unit stores a response time from start of output of driving force required for switching paths until stabilization of the driving force, for each of the paths to be connected. A driving-force correcting unit corrects output level of the driving force, starting correction of the output level of the driving force after the response time for a specified path stored in the response-time storing unit has passed since output of the driving force required for switching to the specified path started.

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: 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: A method of wavelength selection control is disclosed.

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.