Abstract: The present invention addresses the problem of providing a signal process in which a countermeasure against eavesdropping over a physical layer in a wireless communication is performed. An optical signal generation unit 11 generates, as an optical signal, multivalued information that is in a multivalued state and is based on prescribed data. An E/O conversion unit 112 converts the optical signal to an electrical signal. An optical signal amplification unit 12 amplifies the optical signal. An O/E conversion unit 13 converts the optical signal to an electrical signal. A radio wave transmission unit 14 transmits, as a radio wave, the multivalued information converted into the electrical signal. The problem is solved thereby.

Abstract: The purpose of the present invention is to improve signal modulation resolution. A coarse phase modulation element 62A modulates a signal into any of M1 (M1 is an arbitrary integer) patterns in a first range. Fine phase modulation elements 62B-1 through 62B-(k?1) respectively modulate the signal into any of M2 through Mk (M2 through Mk are arbitrary integers that are independent of each other and M1) patterns in a second range through k-th range (k is an integer of 2 or greater). A coarse DAC 61A and DACs 61B-1 through 61B-(k?1) perform control such that the second range through k-th range become narrower than the first range.

Abstract: This invention addresses the problem of improving safety in data transmission/reception, and improving the convenience thereof. A base selection unit 123 of an optical transmission device 1 selects a base for arranging each piece of unit information on an IQ plane. A randomization amount adjustment unit 125 adjusts, on the basis of feedback, the randomization amount in random arrangement of the unit information pieces on the IQ plane. A cryptography signal generation unit 13 generates, as an optical signal, multi-value information equivalent to the random arrangement of the unit information pieces on the IQ plane, within the range of the adjusted randomization amount, in accordance with the selected base. An identification circuit unit 222 of an optical reception device 2 identifies, on the basis of the received optical signal, each of the unit information pieces constituting the multi-value information.

Abstract: The present invention addresses the problem of improving data transmission/reception equipment and transmission efficiency per hour. A light output unit 111 of a light transmitting/receiving device outputs n optical signals (where n is an integer value of 2 or more), each with a different wavelength, based on n respective pieces of data to be transmitted. From the n optical signals, a multiplexer 112 produces an optical signal multiplexed with respect to wavelength. From the multiplexed optical signal, an encryption unit 113 produces an encrypted signal by performing multi-level modulation on the basis of a Y-00 protocol. The problem is solved thereby.

Abstract: The present invention addresses the problem of providing a signal process in which a countermeasure against eavesdropping over a physical layer in a wireless communication is performed. An optical signal generation unit 11 generates, as an optical signal, multivalued information that is in a multivalued state and is based on prescribed data. An E/O conversion unit 112 converts the optical signal to an electrical signal. An optical signal amplification unit 12 amplifies the optical signal. An O/E conversion unit 13 converts the optical signal to an electrical signal. A radio wave transmission unit 14 transmits, as a radio wave, the multivalued information converted into the electrical signal. The problem is solved thereby.

Abstract: The purpose of the present invention is to improve signal modulation resolution. A coarse phase modulation element 62A modulates a signal into any of M1 (M1 is an arbitrary integer) patterns in a first range. Fine phase modulation elements 62B-1 through 62B-(k?1) respectively modulate the signal into any of M2 through Mk (M2 through Mk are arbitrary integers that are independent of each other and M1) patterns in a second range through k-th range (k is an integer of 2 or greater). A coarse DAC 61A and DACs 61B-1 through 61B-(k?1) perform control such that the second range through k-th range become narrower than the first range.

Abstract: An optical amplifier amplifies signal light and includes a pump light source that outputs pump light of a wavelength different from that of the signal light; a combining unit that combines the signal light and the pump light output by the pump light source, to output combined light; an amplifying unit that has non-linear optical media that transmit the combined light to amplify the signal light, the amplifying unit further removing, in the non-linear optical media, idler light generated from the signal light and the pump light, and outputting light that results; and an extraction filter that extracts the signal light from the light output by the amplifying unit.

Abstract: There is provides a wavelength conversion apparatus for converting a wavelength of input signal light and for outputting output signal light of the converted wavelength. The apparatus includes a first and a second nonlinear mediums. The first nonlinear medium receives a first input light and outputs a first output light having a wavelength which is longer than that of the first input light, the wavelength being dependent on optical power of the first input light. The second nonlinear medium receives a second input light and a light output by a light source and outputs a second output light having a wavelength dependent on the wavelengths of the second input light and the light. The first output light is input as the second input light to the second nonlinear medium or the second output light is input as the first input light to the first nonlinear medium.

Abstract: A waveform shaping apparatus includes a quantum dot optical amplifier in which an amplification factor of input signal beams saturates if the optical power of the signal beams is equal to or greater than a predetermined value; and a quantum dot saturable absorber in which an absorption factor of the input signal beams saturates if the optical power of the signal beams is under a predetermined value. The quantum dot optical amplifier and the quantum dot saturable absorber are connected in series with a transmission path of the signal beams, and shape the waveform of the signal beams. Voltages applied to the quantum dot optical amplifier and the quantum dot saturable absorber, respectively, are adjusted based on the optical power of the signal beams.

Abstract: An O/E conversion element converts an input NRZ optical signal into an electric signal. A clock recovery circuit recovers a clock signal from the electric signal obtained by the O/E conversion element. A phase modulator applies phase modulation to the NRZ optical signal, using the recovered clock signal. An intensity modulator applies intensity modulation to the NRZ optical signal, using the recovered clock signal. A dispersion medium compensates for a frequency chirp of an optical signal output from the intensity modulator.

Abstract: There is provides a wavelength conversion apparatus for converting a wavelength of input signal light and for outputting output signal light of the converted wavelength. The apparatus includes a first and a second nonlinear mediums. The first nonlinear medium receives a first input light and outputs a first output light having a wavelength which is longer than that of the first input light, the wavelength being dependent on optical power of the first input light. The second nonlinear medium receives a second input light and a light output by a light source and outputs a second output light having a wavelength dependent on the wavelengths of the second input light and the light. The first output light is input as the second input light to the second nonlinear medium or the second output light is input as the first input light to the first nonlinear medium.

Abstract: In an optical modulation device, an inverter inverts power of a modulation signal light and generates the inverted modulation signal light. A first nonlinear medium phase-modulates a modulated light by a nonlinear optical effect of the modulation signal light. A second nonlinear medium phase-modulates the modulated light by the nonlinear optical effect of the inverted modulation signal light. An optical interference part controls interference between output light from the first nonlinear medium and that from the second nonlinear medium, and produces the phase-modulated modulated light.

Abstract: An optical amplifier amplifies signal light and includes a pump light source that outputs pump light of a wavelength different from that of the signal light; a combining unit that combines the signal light and the pump light output by the pump light source, to output combined light; an amplifying unit that has non-linear optical media that transmit the combined light to amplify the signal light, the amplifying unit further removing, in the non-linear optical media, idler light generated from the signal light and the pump light, and outputting light that results; and an extraction filter that extracts the signal light from the light output by the amplifying unit.

Abstract: In a method and an optical switch by which a signal light is accurately switched even if a polarization state of a signal light inputted has a fluctuation, power of an output light of a polarizer which receives a signal light extracted from an output light of a nonlinear optical medium is monitored and a polarization state of an input signal light to the nonlinear optical medium is controlled so that the power becomes minimum (or maximum). The polarization state of the input signal light is monitored, a calculation of performing a predetermined conversion is executed to the polarization state of the input signal light, and a calculated polarization state is recorded (or recorded without conversion). A polarization state of a control light with respect to the input signal light is monitored and the polarization state of the control light is controlled so as to coincide with the polarization state of the input signal light recorded.

Abstract: According to an aspect of embodiment, an optical switch comprises a signal light input unit, a control light input unit, a first polarization controller, a second polarization controller, a coupler, a nonlinear medium, a monitor and a controller. The first polarization controller controls a polarization of a signal light. The second polarization controller controls a polarization of a control light. The nonlinear medium generates an intensity correlation signal. The monitor monitors a polarization state of light outputted from the nonlinear medium. The controller controls the first polarization controller and the second polarization controller on the basis of the polarization of the signal light and the polarization of the control light.

Abstract: In an optical waveform measurement system, a phase comparator compares phases between an electric signal output from a PD and an electric signal output from a mixer, and outputs a signal having an amplitude proportional to the phase difference of the two electric signals to a VCO via an LPF, as an error signal. A BPF removes a jitter from the electric signal output from the VCO, and a sampling pulse light source outputs sampling light based on the electric signal with the jitter removed. An optical sampling gate samples signal light to be measured with sampling light output from a sampling pulse light source, and the sampled signal light to be measured is measured by an oscilloscope.

Abstract: According to an aspect of an embodiment, an optical switch comprises: a coupler for coupling a signal light and a control pulse; a first nonlinear medium for amplifying the signal light in accordance with the polarization direction of the control pulse light by nonlinear effect; a first polarizer outputting a component light in a signal light and the control pulse light in parallel with the transmission axis of the first polarizer; a second nonlinear medium for changing status of polarization of the signal light by nonlinear effect; and a second polarizer outputting a signal light and a control pulse light in parallel with the transmission axis of the second polarizer.

Abstract: The present invention relates an optical waveform measuring apparatus designed to eliminate the polarization dependency of an intensity correlation signal without a polarization diversity arrangement. The apparatus comprises a sampling light outputting unit for outputting a sampling light pulse to sample light under measurement, a sampling result outputting unit for developing a nonlinear optical effect stemming from the light under measurement and the sampling light pulse from the sampling light outputting unit to output light corresponding to a result of the sampling of the light under measurement, and a polarization state control unit for, before the start of the measurement of the light under measurement, carrying out control on the basis of a power level of the light from the sampling result outputting unit so that a polarization state of the light under measurement, which is to be inputted to the sampling light output unit, is placed into a predetermined state.

Abstract: An optical fiber transmission system including: a first transmission-line optical fiber to input first wavelength signal light output from a transmitter, and to change a waveform of the signal light; an optical coupler to combine the first wavelength signal light that has been propagated through the first transmission-line optical fiber with second wavelength pumping light; an optical limiter to input coupled light output from the optical coupler, saturating a gain as power of the coupled light increases using a nonlinear optical medium, thereby suppressing an optical noise component included in the coupled light, and to output signal light including the first wavelength optical component obtained from the nonlinear optical medium; and a second transmission-line optical fiber to input to a receiver after signal light output from the optical limiter is input and a waveform change by the first transmission-line optical fiber in the signal light is compensated for.

Abstract: An optical signal processing device for shaping a waveform of an optical signal, including: an intensity inversion wavelength converter configured to generate an intensity-modulated optical signal of a second wavelength obtained by inverting a signal intensity of an input intensity-modulated optical signal of a first wavelength; an optical coupler configured to multiplex the intensity-modulated optical signal of the first wavelength and the intensity-modulated optical signal of the second wavelength at a timing at which signal intensities of those signals become opposite; and an optical limiter configured to input coupled light output from the optical coupler, and suppress gain as power of the coupled light becomes higher.