Abstract: To realize sampling (signal measurement) and analysis of a signal to be measured easily at low cost by capturing optical phase fluctuation even when low-speed sampling is carried out.

Abstract: To provide a photodetector which enables reception of massively parallel optical communication, and with which a large volume of data for multi-mode transmission or multi-core transmission can be received instantaneously at once. A photodetector comprising a two-dimensional photodetector array in which a plurality of photodetectors 9 are arranged in a two-dimensional array, and which includes a wire 12 having a width of not more than 4 ?m between the plurality of photodetectors. Each of the photodetectors has a light reception area with a side measuring not more than 100 ?m. The plurality of photodetectors arranged in a two-dimensional array are spaced apart from each other by not less than 20 ?m.

Abstract: To realize sampling (signal measurement) and analysis of a signal to be measured easily at low cost by capturing optical phase fluctuation even when low-speed sampling is carried out.

Abstract: To provide a photodetector which enables reception of massively parallel optical communication, and with which a large volume of data for multi-mode transmission or multi-core transmission can be received instantaneously at once. A photodetector comprising a two-dimensional photodetector array in which a plurality of photodetectors 9 are arranged in a two-dimensional array, and which includes a wire 12 having a width of not more than 4 ?m between the plurality of photodetectors. Each of the photodetectors has a light reception area with a side measuring not more than 100 ?m. The plurality of photodetectors arranged in a two-dimensional array are spaced apart from each other by not less than 20 ?m.

Abstract: To provide an optical comb generation device and an optical comb signal generation method capable of stably generating an optical comb signal having an optical frequency interval exceeding the drive electric signal band of a modulator.

Abstract: To provide an optical comb generation device and an optical comb signal generation method capable of stably generating an optical comb signal having an optical frequency interval exceeding the drive electric signal band of a modulator.

Abstract: To realize collective measurement of ultrawide-band optical signals which have exceeded an electrical band limit. This photodetection device (100) comprises: a time-delay adjustment means (10) into which is input an optical signal that is a detection object; an optical frequency comb generator (20) that generates an optical frequency comb; a photomixer (30) that photomixes optical signal series which are sequentially output from the time delay adjustment means (10) and which were subjected to time adjustment, and the optical frequency comb signal which is output from the optical frequency comb generator (20); and a photodetector (40) that detects the mixed signal output from the photomixer (30). The time delay adjustment means (10) performs time adjustment on the optical signal series so that each of the time adjusted optical signal series is photomixed with the optical frequency comb at different timings in the photomixer (30).

Abstract: To provide a method capable of easily compensating waveform distortion due to a non-linear effect caused by a complicated electric circuit, and a device for implementing the method. Provided are a method capable of effectively compensating signal degradation such as waveform distortion due to a nonlinear effect caused by an optical fiber that is an optical transfer path using an optical phase conjugate signal pair at the time of optical up-conversion or down-conversion, and a device capable of implementing the method. This emission device 25 includes an optical modulator 11, a signal source 13, an optical fiber 15, a multiplexing unit 17, a multiplexing local signal source 19, an optical detector 12, and a transmission antenna 23.

Abstract: To provide a method capable of easily compensating waveform distortion due to a non-linear effect caused by a complicated electric circuit, and a device for implementing the method. Provided are a method capable of effectively compensating signal degradation such as waveform distortion due to a nonlinear effect caused by an optical fiber that is an optical transfer path using an optical phase conjugate signal pair at the time of optical up-conversion or down-conversion, and a device capable of implementing the method. This emission device 25 includes an optical modulator 11, a signal source 13, an optical fiber 15, a multiplexing unit 17, a multiplexing local signal source 19, an optical detector 12, and a transmission antenna 23.

Abstract: To realize collective measurement of ultrawide-band optical signals which have exceeded an electrical band limit. This photodetection device (100) comprises: a time-delay adjustment means (10) into which is input an optical signal that is a detection object; an optical frequency comb generator (20) that generates an optical frequency comb; a photomixer (30) that photomixes optical signal series which are sequentially output from the time delay adjustment means (10) and which were subjected to time adjustment, and the optical frequency comb signal which is output from the optical frequency comb generator (20); and a photodetector (40) that detects the mixed signal output from the photomixer (30). The time delay adjustment means (10) performs time adjustment on the optical signal series so that each of the time adjusted optical signal series is photomixed with the optical frequency comb at different timings in the photomixer (30).

Abstract: It is an object to provide an optical frequency control device or the like which can quickly carry out control over a wide frequency range. The object is achieved by an optical frequency control device or the like comprised of an optical SSB modulator (2), a bias voltage source (3) for applying a bias voltage to the optical SSB modulator (2), and a modulating signal source (4) for applying a modulating signal to the optical SSB modulator (2), wherein the modulating signal source (4) is provided with an arbitrary waveform generator (5) for generating an electrical signal with an arbitrary waveform, and an electrical signal multiplier (6) for multiplying a frequency of the electrical signal generated by the arbitrary waveform generator (5).

Abstract: A quadrature amplitude modulation (QAM) signal generator, which can obtain optical signals such as QAM signals without handling multilevel electrical signals, can be produced by using a plurality of parallel Mach-Zehnder modulators (MZMs), such as quadruplex parallel MZMs (QPMZM). The quadrature amplitude modulation (QAM) signal generator includes a first waveguide, a first quadrature phase-shift-keying (QPSK) signal generator provided on the first waveguide, a second waveguide connected with the first waveguide at a wave-combining point, and a second quadrature phase-shift-keying (QPSK) signal generator provided on the second waveguide.

Abstract: It is an object of the present invention to provide an apparatus that can obtain a multiplied harmonic signal fast and with ease, and the method using the apparatus. The object is attained by the method for obtaining a multiple harmonic signal comprises, suppressing a different parity optical signal having parity different from fundamental optical signals; suppressing residual optical signals using an optical filter after suppressing the different parity optical signal; and obtaining the frequency difference component using the fundamental optical signals, and the device realizing the method.

Abstract: It is an object of the present invention to provide an optical switch system using optical interference. An optical switch system (1) comprises an input part (2) of an optical signal, a branching part (3) of the signal, a main Mach-Zehnder waveguide (MZC) (7), a first intensity modulator (9) provided on a first arm (4) for controlling an amplitude of an optical signal propagating through the first arm (4), a second intensity modulator (10) provided on a second arm (5) for controlling an amplitude of an optical signal propagating through the second arm (5), and a combining part (6) of the signals outputted from the first arm and the second arm, wherein one or both of the branching part (3) and the combining part (6) are X-branched.

Abstract: It is an object of the present invention to provide an apparatus that can obtain a multiplied harmonic signal fast and with ease, and the method using the apparatus. The object is attained by the method for obtaining a multiple harmonic signal comprises, suppressing a different parity optical signal having parity different from fundamental optical signals; suppressing residual optical signals using an optical filter after suppressing the different parity optical signal; and obtaining the frequency difference component using the fundamental optical signals, and the device realizing the method.

Abstract: An optical frequency COM generator generating an optical frequency COM having flat spectrum characteristics using a single modulator. The optical frequency COM generator has a drive signal system (11) and a bias signal system (14) which drive a first drive signal (9), a second drive signal (10) and bias signals (12, 13) to satisfy the following expression (I). ?A+??=?/2 (I). (where, ?A and ?? are defined as ?A?(A1?A2)/2 and ???(?1??2)/2, respectively, A1 and A2 represent the amplitudes of the first and second drive signals when they are inputted to the electrodes of the first and second drive signals, respectively, and ?1 and ?2 represent the phases of bias voltages applied to first and second waveguides, respectively.

Abstract: It is an object of the present invention to provide an optical modulation system capable of suppressing a carrier component (f0) and a high order component (such as a second order component (f0±2fm)). The optical modulation system includes Mach-Zehnder waveguide (8), a first intensity modulator (9) provided on a first arm (4), a second intensity modulator (10) provided on a second arm (5), a first main Mach-Zehnder electrode (MZCA electrode) (13a), and a second main Mach-Zehnder electrode (MZCB electrode) (13b). Non-desired components propagating the respective arms are made to have reverse phase before optical signals are combined, whereby the optical modulation system is capable of suppressing the non-desired components when the optical signals are combined.

Abstract: It is an object of the present invention to provide an apparatus that can obtain a multiplied harmonic signal fast and with ease, and the method using the apparatus. The object is attained by the method for obtaining a multiple harmonic signal comprises, suppressing a different parity optical signal having parity different from fundamental optical signals; suppressing residual optical signals using an optical filter after suppressing the different parity optical signal; and obtaining the frequency difference component using the fundamental optical signals, and the device realizing the method.

Abstract: There is provided an optical modulator capable of controlling the phase of a USB signal and the phase of an LSB signal of an optical FSK modulated signal. A modulation signal is applied to a main Mach-Zehnder electrode (or an electrode C) (11) of a main Mach-Zehnder waveguide (MZC) (8) to switch the USB signal and the LSB signal, and so FSK modulation can be made. In order to control the phase of the optical signal to be outputted from the main Mach-Zehnder waveguide (MZC) (8), bias voltage is applied to the main Mach-Zehnder electrode (11), and the phases of the USB signal and the LSB signal are controlled. By doing so, FSK modulation with adjusted phases can be performed.

Abstract: It is an object of the present invention to provide an optical modulator which is capable of adjusting optical intensity of optical signals which contains non-desired components so that the intensity of the components become at a similar level, whereby the optical modulator is capable of effectively suppressing the non-desired components when the optical signals are combined.