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 FSK demodulator which can be used in the optical information and telecommunications and the like, and which can appropriately demodulate an FSK signal by compensating a delay of an optical FSK modulated signal due to dispersion and the like of an optical fiber. The above-mentioned problem is solved by a frequency shift keying (FSK) demodulator (1) composed of a branching filter (2) for branching an optical signal according to wavelengths thereof; a delay adjusting apparatus (3) for adjusting a delay time of two lights branched by the branching filter; a first photodetector (4) for detecting one optical signal branched by the branching filter; a second photodetector (5) for detecting a remaining optical signal branched by the branching filter; and a means (6) for calculating a difference between an output signal of the first photodetector and an output signal of the second photodetector.

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: The object of the present invention is to provide a modulated optical signal generator utilizing the mechanism of a multiply optical modulator, and a modulated signal generator capable of outputting millimeter waves and the like utilizing the modulated optical signal generator. The above-mentioned object is solved by a modulated optical signal generator (1) provided with an optical modulator (2), a first optical filter (3), and a second optical filter (4), wherein a frequency of a multiplying optical modulation outputted from the second optical filter (4) is controlled by controlling the frequency of the modulating signal inputted to the optical modulator (2).

Abstract: A multiple wavelength signal generation device of the present invention is a multiple wavelength signal generation device having an optical comb generator for obtaining an input light and a group of lights shifted from the input light by predetermined frequencies; and an optical adjusting portion adjusting lights to be inputted to the optical comb generator; wherein the optical comb generator is composed of an optical fiber loop (105) which is provided with an optical SSB modulator (101), an optical amplifier (102) for compensating a conversion loss at the optical SSB modulator, an optical input port (103) for inputting lights from the light source, and an optical output port (104) for outputting lights, and the optical adjusting portion is composed of a phase modulator, an intensity modulator, or a frequency modulator.

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 a multiple wavelength light source capable of generating lights of more wavelengths, and a generation method for multiple wavelength light using a multiple wavelength light source. A multiple wavelength light source of the present invention is a multiple wavelength light source having an optical comb generator for obtaining an input light and a group of lights shifted from the input light by predetermined frequencies; and an optical adjusting portion adjusting lights to be inputted to the optical comb generator; wherein the optical comb generator is composed of an optical fiber loop (105) which is provided with an optical SSB modulator (101), an optical amplifier (102) for compensating a conversion loss at the optical SSB modulator, an optical input port (103) for inputting lights from the light source, and an optical output port (104) for outputting lights, and the optical adjusting portion obtains a plurality of lights having different wavelengths.

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.

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: An optical modulator achieving high extinction ratio and an optical modulator system. By a control system performing an adjustment method comprising predetermined steps by applying a bias voltage daringly to a modulation electrode for switching the USB signal and LSB signal of an established optical SSB modulator or optical FSK modulator, a means for adjusting bias voltage applied to each bias electrode preferably automatically is provided and a bias point where the extinction ratio of an optical modulator is maximized can be obtained.

Abstract: It is an object of the present invention to provide an optical frequency comb generator to generate an optical frequency comb with flat spectral properties using a single modulator. The optical frequency comb generator comprises: a drive signal system (11) and a bias signal system (14) for driving a first drive signal (9), a second drive signals (10), and bias signals (12,13) in accordance with the following Formula (I): ?A±??=?/2??(I) (where ?A and ?? are defined, respectively, as ?A=(A1?A2)/2 and ??=(?1??2)/2, A1 and A2 indicate, respectively, optical phase shift amplitudes guided by the first drive signal and the second drive signal when input into the electrodes, and ?1 and ?2 indicate, respectively, the phases of the bias signals applied to the first waveguide and the second waveguide).

Abstract: It is an object of the present invention to provide a method and a device for automatically calibrating a light intensity measurement device. The device (1) includes an optical switch (3) for switching a route of output from an optical intensity modulator (2), an optical attenuator (5) arranged on a first waveguide (4), a second waveguide (6), a light intensity measurement device (7), a control device (8) for receiving light intensity information measured by the light intensity measurement device (7) and controlling the signal to be applied to the optical intensity modulator (2), and a signal source (9) for receiving a control signal of the control device (8) and adjusting the signal to be applied to the optical intensity modulator (2).

Abstract: The present invention is to provide an optical modulating system for generating a signal of a frequency (f0+2fm) and a signal of a frequency (f0?2fm) and suppressing a signal of a frequency (f0) by a DSB-SC modulator. A fourth harmonic generating system for solving the above problem comprises a first DSB-SC modulator (2) a second DSB-SC modulator (3) and a signal control section (5) for controlling a modulating signal from a signal source (4) for generating modulating signals applied to the first and second DSB-SC modulators (2,3) so that a lower side-band signal (f0) generated by modulating the upper side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) and an upper side-band signal (f0) generated by modulating the lower side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) cancel each other.

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 a DSB-SC system capable of suppressing a third order component. The DSB-SC modulation having high extinction ratio can be realized by adjusting the first order component, which is generated by applying a modulation signal (3fm), and the third order component, which is generated by applying a basic signal (fm), to have reversed phase and the same intensity level, and then by applying the first order component to the third order component, these two components cancel each other.

Abstract: A nested modulator is provided where the circuit arrangement of modifying electrodes including signal electrodes is simplified, and at the same time, the drive voltage can be lowered.

Abstract: In order to provide a reciprocating optical modulation system capable of obtaining a broad bandwidth, a reciprocating optical modulation system (1) of the present invention is basically provided with an optical modulator (2) modulating an output light by controlling one of an intensity, a phase and a frequency of an input light; a first fiber grating (3) transmitting a light of a predetermined frequency domain among lights inputted to and outputted from the optical modulator while reflecting lights of other frequencies; a second fiber grating (4) transmitting a light of a predetermined frequency domain among lights inputted to and outputted from the optical modulator while reflecting lights of other frequencies; and a signal source (5) generating a modulating signal to be inputted to the optical modulator (2).

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: 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 ?2represent the phases of bias voltages applied to first and second waveguides, respectively.

Abstract: It is an object of the present invention to provide a multiple wavelength light source capable of generating lights of more wavelengths, and a generation method for multiple wavelength light using a multiple wavelength light source. A multiple wavelength light source of the present invention is a multiple wavelength light source having an optical comb generator for obtaining an input light and a group of lights shifted from the input light by predetermined frequencies; and an optical adjusting portion adjusting lights to be inputted to the optical comb generator; wherein the optical comb generator is composed of an optical fiber loop (105) which is provided with an optical SSB modulator (101), an optical amplifier (102) for compensating a conversion loss at the optical SSB modulator, an optical input port (103) for inputting lights from the light source, and an optical output port (104) for outputting lights, and the optical adjusting portion obtains a plurality of lights having different wavelengths.