Patents by Inventor Masatoshi Suzuki
Masatoshi Suzuki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6028695Abstract: When an intensity modulating operation and a phase modulating operation are carried out by employing a 2-electrode MachZehnder type optical modulator preferably a LN-MZ type optical modulator, a drive signal of this 2-electrode LN-MZ type optical modulator is produced from an intensity modulation signal and a phase modulation signal with a low loss and a simple arrangement.Type: GrantFiled: July 30, 1998Date of Patent: February 22, 2000Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Aritomo Uemura, Takashi Mizuochi, Katsuhiro Shimizu, Kiwami Matsushita, Tadayoshi Kitayama, Masatoshi Suzuki, Hidenori Taga, Shu Yamamoto
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Patent number: 6021235Abstract: A new two-way WDM optical transmission system is provided. The WDM optical transmission system comprises a two-way optical fiber cable, a first dispersion compensation optical fiber (DCOF) connected to one end of the optical fiber cable, a second DCOF connected to another end of the optical fiber cable, a chromatic dispersion compensating transmitter unit and a chromatic dispersion compensating receiver unit. The two-way optical fiber cable comprises a plurality of segments. The first DCOF is connected to one end of the optical fiber cable and has a compensation amount of a half of a one segment dispersion D.sub.c of the optical fiber cable. The second DCOF is connected to another end of the optical fiber cable and has the compensation amount of the half of the one segment dispersion D.sub.c. And the chromatic dispersion compensating transmitter unit compensates accumulated residual chromatic dispersions to be caused by higher-order wavelength dispersion of the optical fiber cable at each signal wavelength.Type: GrantFiled: July 31, 1998Date of Patent: February 1, 2000Assignee: Kokusai Denshin Denwa Kabushiki-KaishaInventors: Shu Yamamoto, Hidenori Taga, Masatoshi Suzuki, Noboru Edagawa, Shigeyuki Akiba
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Patent number: 6005702Abstract: An optical transmission device using return-to-zero optical pulses as transmission optical pulses, which is capable of enhancing a transmission distance as well as a wavelength range with satisfactory transmission characteristics and enabling an easy realization of the wavelength division multiplexing optical transmission. The optical transmission device is formed by an optical transmitter for transmitting transmission optical pulses by superposing digital data signals onto return-to-zero optical pulses, and a modulator for applying one of a phase modulation and a frequency modulation in synchronization with a transmission rate of the transmission optical pulses, to the transmission optical pulses transmitted by the optical transmitter. This optical transmission device can be utilized in forming a wavelength division multiplexing optical transmission apparatus and an optical transmission system.Type: GrantFiled: February 19, 1997Date of Patent: December 21, 1999Assignee: Kokusai Denshin Denwa Kabushiki-KaishaInventors: Masatoshi Suzuki, Itsuro Morita, Noboru Edagawa, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5978529Abstract: This invention provides the gain equalizer positioned to an optical amplifying transmission line for equalizing gains of said optical amplifying transmission line, comprising a plurality of first optical filters varying transmittance periodically in at least predetermined wavelength range, and one or more second optical filters that their transmittance peaks at a wavelength substantially coinciding to the predetermined transmittance bottom wavelength of the first optical filters and decreases in a predetermined range at both side of the predetermined transmittance bottom wavelength.Type: GrantFiled: March 6, 1998Date of Patent: November 2, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Hidenori Taga, Noriyuki Takeda, Masatoshi Suzuki, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5966228Abstract: An optical transmission system comprises transmission optical fibers 14 connected between an optical transmission terminal 10 and an optical receiving terminal 12 via optical amplifying repeaters 16, and equalizing fiber 18 each connected in each equalizing interval. The equalizing fiber 18 is typically located at the terminal end of each equalizing interval. Each transmission optical fiber 14 is a dispersion-shifted fiber whose wavelength dispersion is substantially zero in a specific band, for example, 1.5 .mu.m. The optical amplifying repeaters 16 include an optical amplifier, and a dispersion compensating optical element having wavelength dispersion characteristics that exhibit an inclination opposite from that of wavelength characteristics of wavelength dispersion of the transmission optical fiber 14 (more specifically, a minus inclination with respect to the wavelength). The dispersion compensating optical element compensates offset values of cumulative wavelength dispersion among different wavelengths.Type: GrantFiled: November 26, 1996Date of Patent: October 12, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Shigeyuki Akiba, Shu Yamamoto, Masatoshi Suzuki, Noboru Edagawa, Hidenori Taga
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Patent number: 5959764Abstract: A waveform converter includes a transmission-type InGaAsP electroabsorption optical modulator 10 using the Franz-Keldysh effect. Continuous light (probe light) 12 as a target of wavelength conversion is fed to an end surface 10a of the optical modulator 10 while a constant voltage of 3 V is applied to the optical modulator 10. An optical circulator 14 is supplied with original signal light (signal light to be waveform-converted) 16 through its terminal A, and delivers it from the terminal B thereof to another end surface 10b of the optical modulator 10. The optical modulator 10 gives a loss to the probe light 12 according to the intensity of the original signal light 16 and makes the waveform of the probe light 12 to be substantially the same as the original signal light. The probe light waveform-converted by the optical modulator 10 and output from the end surface 10b is fed to a terminal B of an optical circulator 14 as a waveform-converted light 18 and output from its terminal C.Type: GrantFiled: September 4, 1997Date of Patent: September 28, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Noboru Edagawa, Masatoshi Suzuki, Shu Yamamoto
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Patent number: 5898714Abstract: An optical pulse generator, capable of generating ultrashort optical pulses suitable for optical soliton transmission, includes a DFB laser 10 for continuous laser oscillation, an electroabsorbtion modulator 12 for creating a sequence of optical pulses of the pulse width 14.6 ps from optical output of the laser 10. Output from an optical modulator 12 enters into a dispersion decreasing fiber 16 via an optical isolator 14. The dispersion decreasing fiber 16 has chromatic dispersion that decreases from 13.7 ps/nm/km to 2.3 ps/nm/km with distance, and its fiber length is 15 km. Pump laser beams from pump lasers 20, 24 are introduced to the dispersion decreasing fiber 16 by optical couplers 18, 22, and the fiber 16 functions as a Raman amplifier. When the Raman gain is 2.4 dB, the pulse width is compressed from 14.6 ps to 5.8 ps, approximately, even when the power of input pulses to the dispersion decreasing fiber 16 complies with the soliton condition.Type: GrantFiled: January 13, 1997Date of Patent: April 27, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Itsuro Morita, Noboru Edagawa, Masatoshi Suzuki, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5892608Abstract: An optical transmitter which reverses the ON-OFF state of the optical intensity of a bright soliton lightwave and generates a dark soliton lightwave having an optical phase shift, an optical receiver for the dark soliton lightwave, and a superfast, high-capacity optical transmission system which is capable of increasing the soliton pulse array density while suppressing timing jitter. The optical transmission system is provided with the optical transmitter which transmits a dark soliton lightwave having digital information, the optical receiver which receives the dark soliton lightwave as a return-to-zero pulse and a transmission optical fiber interconnecting the transmitter and the receiver.Type: GrantFiled: December 20, 1996Date of Patent: April 6, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Masatoshi Suzuki, Noboru Edagawa, Hidenori Taga, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5889607Abstract: Incident light 1 is inputted to an electro-absorption-type optical modulator 4 via an optical circulator 2 and a lens 3, and subjected to intensity modulation that corresponds to a modulation signal 8. The optical signal outputted by the electro-absorption-type optical modulator 4 is inputted to a Faraday rotator 6 via a lens 5, and the plane of polarization is rotated 45.degree.. The optical signal transmitted by the Faraday rotator 6 is totally reflected by a totally reflecting mirror 7, inputted for the second time to the Faraday rotator 6, then passed through the lens 5 after the plane of polarization has been rotated 45.degree. by this Faraday rotator 6, and readmitted by the electro-absorption-type optical modulator 4. The output of the electro-absorption-type optical modulator 4 is emitted via the lens 3 and the optical circulator 2. The polarization dependence of insertion loss can be eliminated because the plane of polarization is rotated 90.degree.Type: GrantFiled: June 4, 1997Date of Patent: March 30, 1999Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Masatoshi Suzuki, Noboru Edagawa, Itsuro Morita, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5883734Abstract: An optical switch is formed by: at least one switch driving circuit for generating ultrasonic waves; at least one electric acousto-optic element forming at least one diffraction grating therein upon being applied with the ultrasonic waves generated by the switch driving circuit; at least one polarization rotator for rotating a polarization plane of a first primary diffracted light produced by the diffraction grating, by 90.degree.Type: GrantFiled: April 10, 1997Date of Patent: March 16, 1999Assignee: Kokusai Denshin Denwa Kabushiki-KaishaInventors: Masatoshi Suzuki, Shigeyuki Akiba
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Patent number: 5874663Abstract: An air-fuel ratio sensor is provided in which sensor lead wires are held by a rubber bush at an end of a sensor housing. The rubber bush is made of a rubber material having a 100% modulus strength equal to or larger than 60 Kgf/cm.sup.2 even after the sensor is used under a temperature environment of 300.degree. C. for 100 hours.Type: GrantFiled: January 21, 1997Date of Patent: February 23, 1999Assignee: Denso CorporationInventors: Kenji Fukaya, Makoto Hori, Masahiro Hamaya, Masatoshi Suzuki
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Patent number: 5864421Abstract: An optical frequency shifter which has no insertion loss polarization dependency and no polarization mode dispersion is formed by: at least one ultrasonic wave generator for generating ultrasonic waves; at least one electric acousto-optic element forming at least one diffraction grating therein upon being applied with the ultrasonic waves generated by the ultrasonic wave generator; at least one polarization rotator for rotating a polarization plane of a first primary diffracted light produced by the diffraction grating, by 90.degree.Type: GrantFiled: May 28, 1997Date of Patent: January 26, 1999Assignee: Kokusai Denshin Denwa Kabushiki-KaishaInventors: Masatoshi Suzuki, Noboru Edagawa, Itsuro Morita, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5825144Abstract: The invention relates to a drive control apparatus for a rotating machine having a movable part which is rotatably driven by a motor.The apparatus has a fail-safe construction which gives an output of logic value "1" when the movable part is stopped, wherein, to enable supply of motor current to start a motor (2) at the motor start-up time under a condition of the movable part stopped, motor drive permission is granted by a logical product output which is obtained by a logical product operation of a start signal generated by switching a start switch on, and a logical sum output obtained by a logical sum operation of an output of a current sensor (3) generating an output of logic value "1" when the motor current does not flow and an output of a rotation sensor (4) generating an output of logic value "1" when the movable part is rotating.Type: GrantFiled: July 16, 1995Date of Patent: October 20, 1998Assignees: Kao Corporation, The Nippon Signal Co., Ltd.Inventors: Masatoshi Suzuki, Koichi Futsuhara, Masayoshi Sakai
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Patent number: 5808789Abstract: An optically amplifying transmission system available for wider signal bands includes an optical transmission line 42 divided into two sections 42a and 42b, optically amplifying repeaters 48a having 7 m-long erbium-doped optical fibers to repeat transmission optical fibers 46a in the section 42a, and optically amplifying repeaters 48b having 10.8 m-long erbium-doped optical fibers to repeat transmission optical fibers 46b in the section 42b. The transmission optical fibers 46a an 46b are optical fibers absolutely identical in construction and length.Type: GrantFiled: June 12, 1997Date of Patent: September 15, 1998Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Noboru Edagawa, Hidenori Taga, Masatoshi Suzuki, Itsuro Morita, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5798856Abstract: The short optical pulse generator is provided with a semiconductor laser which oscillates continuously at a single wavelength, a semiconductor electro-absorption type optical modulator which performs the intensity modulation of the output light from the laser, and a sinusoidal voltage generator and a DC voltage generator for driving the electro-absorption type optical modulator. A DC voltage is applied to the electro-absorption type optical modulator so that the output light from the laser is sufficiently extinguished. By applying a sinusoidal voltage to the optical modulator, short optical pulses are generated.Type: GrantFiled: November 16, 1994Date of Patent: August 25, 1998Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Masatoshi Suzuki, Hideaki Tanaka, Yuichi Matsushima
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Patent number: 5798871Abstract: A zoom lens is composed of a first lens group of a negative refractive power, a second lens group of a positive refractive power and a third lens group of a positive refractive power, in which, in the zooming operation from the wide angle end to the telephoto end, the distance between the first and second lens groups decreases and the distance between the second and third lens groups varies.Type: GrantFiled: October 25, 1996Date of Patent: August 25, 1998Assignee: Nikon CorporationInventors: Atsushi Shibayama, Masatoshi Suzuki, Takanori Fujita
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Patent number: 5786918Abstract: An optical communication system of a construction wherein the average wavelength dispersion value of the transmission optical fiber used, the optical output intensity of each optical amplifier repeater inserted in the transmission optical fiber and the widths of return-to-zero optical pulses transmitted over the transmission line are determined so as to compensate for the pulse compression effect by the nonlinear optical effect produced on the optical pulses by the pulse spreading effect by the wavelength dispersion effect. An optical multiplexer in the optical transmitting device time-division multiplexes the return-to-zero optical pulses, and the optical multiplexed signal is provided as an alternating-amplitude optical signal with the amplitudes of the return-to-zero optical pulses alternated.Type: GrantFiled: December 19, 1995Date of Patent: July 28, 1998Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Masatoshi Suzuki, Hidenori Taga, Noboru Edagawa, Hideaki Tanaka, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5737110Abstract: An optical transmitter which reverses the ON-OFF state of the optical intensity of a bright soliton lightwave and generates a dark soliton lightwave having an optical phase shift, an optical receiver for the dark soliton lightwave, and a superfast, high-capacity optical transmission system which is capable of increasing the soliton pulse array density while suppressing timing jitter. The optical transmission system is provided with the optical transmitter which transmits a dark soliton lightwave having digital information, the optical receiver which receives the dark soliton lightwave as a return-to-zero pulse and a transmission optical fiber interconnecting the transmitter and the receiver.Type: GrantFiled: December 20, 1996Date of Patent: April 7, 1998Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Masatoshi Suzuki, Noboru Edagawa, Hidenori Taga, Shu Yamamoto, Shigeyuki Akiba
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Patent number: 5726789Abstract: A device for modulating optical short pulses, while preventing a pulse compression optical fiber from degradation of the transmission characteristics even if the length of the pulse compression optical fiber varies, utilizes an optical short pulse generator 1, a pulse compression optical fiber 2, an optical divider 3, a photodetector 6, an amplifier 7, a band pass filter 8, a phase comparator 9, a loop filter 11, and a driving signal generator 12. The loop which comprises loop filter 11 and driving signal generator 12 controls an oscillation frequency in a VCO 12-1 so that the phase of a compressed optical pulse fed to an optical intensity modulator 4 is identical to the phase of a data signal that is synchronized with a reference clock and used to modulate the compressed optical pulse. In this manner, the extinction ratio of the modulation output is not degraded even if the length of the pulse compression optical fiber 2 varies due to ambient temperature variations.Type: GrantFiled: March 19, 1996Date of Patent: March 10, 1998Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Yukio Horiuchi, Masatoshi Suzuki
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Patent number: 5721642Abstract: A zoom lens is composed of a first lens group of a negative refractive power, a second lens group of a positive refractive power and a third lens group of a positive refractive power, in which, in the zooming operation from the wide angle end to the telephoto end, the distance between the first and second lens groups decreases and the distance between the second and third lens groups varies.Type: GrantFiled: October 25, 1996Date of Patent: February 24, 1998Assignee: Nikon CorporationInventors: Atsushi Shibayama, Masatoshi Suzuki, Takanori Fujita