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: 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: An optical switch which minimizes losses in the power of output light while enabling deflection of light within a range of comparatively large deflection angles used for setting switching among output ports. The optical switch is configured to have a first light deflection element deflecting the input light at an angle appropriate to a position of an designated port with an applied first drive voltage; and a second light deflection element finely adjusting a deflection angle of the light output from the first deflection element to the designated port with an applied second drive voltage such that power of light output from the designated port becomes maximum.

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: 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 encryption technique allowing use of classic Y-00 scheme performed using classic physical random numbers instead of quantum fluctuation in electrical communication and data storage in recording media, including a first modulation step for multilevel-modulating input data by associating with specific state pairs determined by physical random numbers, a second modulation step for outputting the output of the first step by irregularly associating with another signal by physical random numbers, and a channel coding step for channel-coding the output of the second step into desired codeword and outputting it as encrypted data, wherein the decoded signal obtained by channel-decoding the encrypted data can be discriminated which of specific state pairs the signal corresponds to and demodulated into the input data, and output by the first modulation by state pairs other than the specific state pairs and the second modulation by a physical random number different from the physical random number.

Abstract: Electrolytic manganese dioxide characterized by having a surface sulfate (SO4) content of smaller than 0.10% by weight and a JIS-pH value, as measured according to JIS K1467, of at least 1.5 but smaller than 3.5, preferably at least 2.1 but smaller than 3.2 is provided. Preferably 3% to 25% in number of the fine particles of the manganese dioxide have a particle diameter of not larger than 1 ?m. A battery provided with a cathode made from the electrolytic manganese dioxide as active material exhibits good high-rate discharge characteristics and good resistance to metal corrosion.

Abstract: An encryption technique having a greater encryption strength than conventional mathematical encryption by using classic physical random numbers etc., including a step for modulating one-bit input data into a coded signal by associating it with a discrete value of at least two bits determined by pseudo random numbers and physical random numbers and a step for channel-coding and outputting the coded signal, wherein 1) the coded signal can be demodulated into the input data by the pseudo random number, 2) the number of sets of input data, pseudo random number, and physical random number corresponding to a particular discrete value is equal for two values of the input data, and 3) the number of sets of pseudo random number and physical random number corresponding to respective values of the input data and respective values of the discrete value is equally associated also with any set of them.

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: In an optical unit having a holding structure which brings a junk ring or the like into contact with an optical surface of a lens, the optical surface suffers from a serious elastic deformation leading to deterioration of optical performance. Upon holding the lens, therefore, a face other than the optical surface is provided on the lens so that the lens is held by applying a force to the face from element holding members.

Abstract: An optical switch which minimizes losses in the power of output light while enabling deflection of light within a range of comparatively large deflection angles used for setting switching among output ports. The optical switch is configured to have a first light deflection element deflecting the input light at an angle appropriate to a position of an designated port with an applied first drive voltage; and a second light deflection element finely adjusting a deflection angle of the light output from the first deflection element to the designated port with an applied second drive voltage such that power of light output from the designated port becomes maximum.

Abstract: In an optical unit having a holding structure which brings a junk ring or the like into contact with an optical surface of a lens, the optical surface suffers from a serious elastic deformation leading to deterioration of optical performance. Upon holding the lens, therefore, a face other than the optical surface is provided on the lens so that the lens is held by applying a force to the face from element holding members.

Abstract: In an optical unit having a holding structure which brings a junk ring or the like into contact with an optical surface of a lens, the optical surface suffers from a serious elastic deformation leading to deterioration of optical performance. Upon holding the lens, therefore, a face other than the optical surface is provided on the lens so that the lens is held by applying a force to the face from element holding members.

Abstract: The present invention has an object of providing a variable optical filter that can move its periodic filter characteristic over a wide range in parallel to an optical frequency axis direction. To this end, the variable optical filter of the present invention comprises: first and second filter sections connected in series via an optical path, and a control section for controlling the periodic filter characteristic of each of the first and second filter sections. The control section, when the filter characteristic of one of the first and second filter sections is required to move in parallel to the optical frequency axis direction to exceed a variable range, relatively controls the filter characteristic of each of the first and second filter sections such that the switching is performed from one filter section to the other filter section, provided that the filter characteristic of the overall variable optical filters becomes constant.

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: 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: 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: By connecting a plurality of VIPA type wavelength dispersion compensators, each compensating for wavelength dispersion of a different order by a plurality of optical circulators and sequentially inputting input light to each VIPA type wavelength dispersion compensator, light, even the higher-order wavelength dispersion of which is compensated for, is outputted as output light.