Patents by Inventor Hiroshi Kuzukami
Hiroshi Kuzukami 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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Publication number: 20160204569Abstract: An optical transmitter includes: a wavelength tunable light source; an etalon filter that filters output light of the light source; a measurement unit that generates a monitor value corresponding to power of output light of the etalon filter; and a controller that controls a temperature of the light source and a temperature of the etalon filter. Until the wavelength of the output light of the light source is adjusted to a target wavelength, the controller alternately performs first processing to control the temperature of the light source based on the monitor value so as to shift the wavelength of the output light of the light source by a specified amount, and second processing to control the temperature of the etalon filter based on the monitor value so as to shift the transmission characteristics of the etalon filter by the specified amount.Type: ApplicationFiled: November 20, 2015Publication date: July 14, 2016Applicant: Fujitsu Optical Components LimitedInventor: Hiroshi Kuzukami
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Patent number: 8364045Abstract: An optical transmission device in which: a first cyclic filter with a fixed transmission wavelength characteristic and a second cyclic filter with a variable transmission wavelength characteristic are combined, and the transmission wavelength characteristic of the second cyclic filter is changed according to a target wavelength, to thereby control the relative phase relationship of the transmission wavelength characteristics of the first and second cyclic filters. Moreover a light source is controlled according to a monitored value of the transmittance of the second cyclic filter with respect to the control target light, to thereby match the wavelength of the control target light with the target wavelength. Consequently, it is possible, with a simple configuration using a combination of two cyclic filters, to variably control wavelength at arbitrary wavelength intervals at a high level of precision.Type: GrantFiled: August 13, 2010Date of Patent: January 29, 2013Assignee: Fujitsu Optical Components LimitedInventors: Tomohisa Ishikawa, Hiroshi Kuzukami
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Publication number: 20110052207Abstract: An optical transmission device in which: a first cyclic filter with a fixed transmission wavelength characteristic and a second cyclic filter with a variable transmission wavelength characteristic are combined, and the transmission wavelength characteristic of the second cyclic filter is changed according to a target wavelength, to thereby control the relative phase relationship of the transmission wavelength characteristics of the first and second cyclic filters. Moreover a light source is controlled according to a monitored value of the transmittance of the second cyclic filter with respect to the control target light, to thereby match the wavelength of the control target light with the target wavelength. Consequently, it is possible, with a simple configuration using a combination of two cyclic filters, to variably control wavelength at arbitrary wavelength intervals at a high level of precision.Type: ApplicationFiled: August 13, 2010Publication date: March 3, 2011Applicant: Fujitsu Optical Components LimitedInventors: Tomohisa Ishikawa, Hiroshi Kuzukami
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Publication number: 20100246621Abstract: A light source control apparatus includes a laser having a wavelength that varies depending on temperature; a wavelength monitor that monitors the wavelength of light output from the laser; a temperature controller that controls the temperature of the laser based on an output of the wavelength monitor; a temperature monitor that monitors the temperature of the laser; and a control manager that stops control by the temperature controller if a variation amount per unit time of the temperature monitored by the temperature monitor exceeds a threshold value.Type: ApplicationFiled: February 12, 2010Publication date: September 30, 2010Applicant: FUJITSU LIMITEDInventor: Hiroshi Kuzukami
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Patent number: 7769304Abstract: A signal processing apparatus sets a discrimination level most suitably, regardless of whether the apparatus is in the minimum receiving system or the maximum receiving system. The apparatus comprises a light receiving unit converting input signal light to an electric signal, and a level detecting unit for detecting a high level component and a low level component of the electric signal from the light receiving unit, along with peak levels on a high-side and a low-side of the electric signal.Type: GrantFiled: December 27, 2006Date of Patent: August 3, 2010Assignee: Fujitsu LimitedInventors: Hisaya Sakamoto, Toru Yamazaki, Yoshito Anazawa, Hiroshi Kuzukami
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Publication number: 20090324256Abstract: In an optical transmitter, a laser emits light. A laser driving controller controls driving of the laser by superimposing modulation signals on laser driving signals to generate laser driving superimposed signals and by applying the laser driving superimposed signals to the laser to cause wavelength fluctuations in laser output light to suppress nonlinear optical phenomena during optical fiber transmission. An optical power variable controller variably controls a power of the laser output light. An optical fluctuation compensator suppresses optical fluctuations by monitoring output light from the variable controller to detect optical fluctuations accompanying wavelength fluctuations from monitoring results and by controlling a gain of the variable controller.Type: ApplicationFiled: February 26, 2009Publication date: December 31, 2009Applicant: FUJITSU LIMITEDInventors: Hiroshi Kuzukami, Tsuyoshi Morishita
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Publication number: 20070146795Abstract: A signal processing apparatus sets a discrimination level most suitably, regardless of whether the apparatus is in the minimum receiving system or the maximum receiving system. The apparatus comprises a light receiving unit converting input signal light to an electric signal, and a level detecting unit for detecting a high level component and a low level component of the electric signal from the light receiving unit, along with peak levels on a high-side and a low-side of the electric signal.Type: ApplicationFiled: December 27, 2006Publication date: June 28, 2007Applicant: FUJITSU LIMITEDInventors: Hisaya Sakamoto, Toru Yamazaki, Yoshito Anazawa, Hiroshi Kuzukami
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Publication number: 20030231891Abstract: An optical transmitter is capable of constantly operating at an optimal operating point, even when a polarization angle varies, which is realized by an operation processing device controlling such that a predetermined range of an input-and-output characteristic of a modulator is scanned in order to obtain a bias voltage point that gives an optimal operation range, and an operation point controlling circuit controlling the operation range by a feedback control with the detected bias voltage point as a starting point.Type: ApplicationFiled: January 21, 2003Publication date: December 18, 2003Applicant: FUJITSU LIMITEDInventors: Hiroshi Kuzukami, Kazuhiro Suzuki, Rumiko Tashiro, Kakuji Inoue, Hiroshi Yamada
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Patent number: 5732096Abstract: The control circuit for supplying a driving current to a laser diode makes it possible to keep the laser driving current variable in a wide range.Type: GrantFiled: May 31, 1996Date of Patent: March 24, 1998Assignee: Fujitsu LimitedInventors: Kazuhiro Suzuki, Hiroshi Kuzukami, Yuji Miyaki, Akihiko Yasuda, Yoshinori Ohkuma
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Patent number: 5625181Abstract: A light receipt system has a bias circuit and a light-receipt element. The bias circuit controls light input power to the light-receipt element to the optimum multiplication factor. The bias circuit of the light-receipt element has a first resistor, a second resistor, and a third resistor. The first resistor and the second resistor are connected in parallel, and the light-receipt element is connected between a connection of the first resistor and the second resistor, and the third resistor. A bypass current path is provided, connected to a junction point between the first resistor and the second resistor.Type: GrantFiled: August 10, 1994Date of Patent: April 29, 1997Assignee: Fujitsu LimitedInventors: Akihiko Yasuda, Setsuo Misaizu, Hisaya Sakamoto, Yuji Miyaki, Norio Nagase, Hiroshi Kuzukami