Patents by Inventor Yoichi Akasaka
Yoichi Akasaka 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).
-
Patent number: 10020878Abstract: An optical signal-to-noise ratio monitor includes: a measuring unit that measures an optical signal-to-noise ratio of a polarization multiplexed optical signal, a polarization state of the polarization multiplexed optical signal changing with respect to time; a selector that selects, from a plurality of optical signal-to-noise ratios measured by the measuring unit at a plurality of measurement points within a designated measurement period, an optical signal-to-noise ratio that is higher than an average of the plurality of optical signal-to-noise ratios; and an output unit that outputs the optical signal-to-noise ratio selected by the selector.Type: GrantFiled: April 17, 2015Date of Patent: July 10, 2018Assignee: FUJITSU LIMITEDInventors: Shoichiro Oda, Yasuhiko Aoki, Hiroki Oi, Satoru Okano, Yoichi Akasaka, Jeng-Yuan Yang
-
Publication number: 20160308611Abstract: An optical signal-to-noise ratio monitor includes: a measuring unit that measures an optical signal-to-noise ratio of a polarization multiplexed optical signal, a polarization state of the polarization multiplexed optical signal changing with respect to time; a selector that selects, from a plurality of optical signal-to-noise ratios measured by the measuring unit at a plurality of measurement points within a designated measurement period, an optical signal-to-noise ratio that is higher than an average of the plurality of optical signal-to-noise ratios; and an output unit that outputs the optical signal-to-noise ratio selected by the selector.Type: ApplicationFiled: April 17, 2015Publication date: October 20, 2016Applicant: Fujitsu LimitedInventors: Shoichiro ODA, Yasuhiko AOKI, Hiroki Oi, Satoru OKANO, Yoichi AKASAKA, Jeng-Yuan YANG
-
Patent number: 9246624Abstract: A method and system for amplifying optical signals includes generating idler signals for input signals using a pump signal at a first non-linear element (NLE). Phase and amplitude regulation is performed using the output from the first NLE. Optical power monitoring of the input signals may be used for power equalization. The phase regulation may use input from a feed forward phase-power monitoring of the output phase-sensitive amplified signal. After phase regulation the phase-sensitive amplified signal is generated at a second NLE using the pump signal. Optical power monitoring of the input signals may be used for power equalization and other control functions to achieve low-noise operation.Type: GrantFiled: September 5, 2014Date of Patent: January 26, 2016Assignee: Fujitsu LimitedInventors: Jeng-Yuan Yang, Yoichi Akasaka, Motoyoshi Sekiya
-
Patent number: 9030730Abstract: A method for amplifying optical signals includes determining a source optical signal, generating a first resultant signal including a pump signal and the source optical signal, sending the first resultant signal through a non-linear element to generate a second resultant signal including the first resultant signal and an idler signal, and sending the second resultant signal through a non-linear element to perform phase-sensitive amplification. The phase-sensitive amplification results in a third resultant signal including an amplified source optical signal, the pump signal, and the idler signal. The method also includes filtering the third resultant signal to remove the pump signal and the idler signal and outputting the amplified source optical signal.Type: GrantFiled: January 14, 2013Date of Patent: May 12, 2015Assignee: Fujitsu LimitedInventors: Jeng-Yuan Yang, Motoyoshi Sekiya, Yoichi Akasaka
-
Publication number: 20140198375Abstract: A method for amplifying optical signals includes determining a source optical signal, generating a first resultant signal including a pump signal and the source optical signal, sending the first resultant signal through a non-linear element to generate a second resultant signal including the first resultant signal and an idler signal, and sending the second resultant signal through a non-linear element to perform phase-sensitive amplification. The phase-sensitive amplification results in a third resultant signal including an amplified source optical signal, the pump signal, and the idler signal. The method also includes filtering the third resultant signal to remove the pump signal and the idler signal and outputting the amplified source optical signal.Type: ApplicationFiled: January 14, 2013Publication date: July 17, 2014Applicant: FUJITSU LIMITEDInventors: Jeng-Yuan Yang, Motoyoshi Sekiya, Yoichi Akasaka
-
Patent number: 7684706Abstract: In accordance with the teachings of the present invention, a system and method for traffic distribution in an optical network is provided. In a particular embodiment, a traffic distribution module in a passive optical network (PON), includes a filter configured to receive downstream traffic in a first set of one or more wavelengths and a second set of one or more wavelengths from an optical line terminal (OLT), direct the traffic in the first set of wavelengths to a primary power splitter, and direct the traffic in the second set of wavelengths to a first connector. The traffic distribution module also includes a primary power splitter and a plurality of secondary power splitters. The primary power splitter is configured to receive the traffic in the first set of wavelengths and distribute the traffic in the first set to the plurality of secondary power splitters coupled to the primary power splitter such that optical network units (ONUs) in the PON receive the traffic in the first set of wavelengths.Type: GrantFiled: June 27, 2006Date of Patent: March 23, 2010Assignee: Fujitsu LimitedInventors: Yoichi Akasaka, Martin Bouda, Takao Naito
-
Publication number: 20070092249Abstract: In accordance with the teachings of the present invention, a system and method for traffic distribution in an optical network is provided. In a particular embodiment, a traffic distribution module in a passive optical network (PON), includes a filter configured to receive downstream traffic in a first set of one or more wavelengths and a second set of one or more wavelengths from an optical line terminal (OLT), direct the traffic in the first set of wavelengths to a primary power splitter, and direct the traffic in the second set of wavelengths to a first connector. The traffic distribution module also includes a primary power splitter and a plurality of secondary power splitters. The primary power splitter is configured to receive the traffic in the first set of wavelengths and distribute the traffic in the first set to the plurality of secondary power splitters coupled to the primary power splitter such that optical network units (ONUs) in the PON receive the traffic in the first set of wavelengths.Type: ApplicationFiled: June 27, 2006Publication date: April 26, 2007Inventors: Yoichi Akasaka, Martin Bouda, Takao Naito
-
Patent number: 4948742Abstract: Oxygen ions or nitrogen ions are implanted into a semiconductor substrate to form a dielectric layer in the semiconductor substrate. An epitaxial semiconductor layer of at least 2 .mu.m in thickness, having excellent reproducibility and good crystallinity, is formed on a residual semiconductor layer on the dielectric layer by epitaxial growth, to serve as a region for forming semiconductor elements. Thus, a semiconductor device having high isolation breakdown voltage is impemented.Further, both oxygen ions and nitrogen ions are respectively implanted into a portions of a semiconductor substrate, which are adjacent to each other along the direction of thickness, to form two dielectric layers. Thus, a semiconductor device having higher isolation breakdown voltage is implemented.Type: GrantFiled: November 20, 1989Date of Patent: August 14, 1990Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tadashi Nishimura, Yoichi Akasaka
-
Patent number: 4899206Abstract: Described is a semiconductor device comprising a metal wiring formed on a semiconductor wiring including a device or devices, wherein impurities are injected into the metal wiring by ion implantation for suppressing the whiskers that may otherwise develop during processing of the metal wiring. Shorting among the wiring layers caused by such whiskers may be suppressed and the yield rate and operational reliability of the semiconductor device may be improved.Type: GrantFiled: April 1, 1985Date of Patent: February 6, 1990Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiromi Sakurai, Yoichi Akasaka
-
Patent number: 4797723Abstract: A stacked semiconductor device includes a first integrated circuit formed on the principal surface of a semiconductor layer and containing active elements, and a second integrated circuit formed on the first integrated circuit through an insulation layer and containing active elements. The second integrated circuit is formed on that part of the surface of the first integrated circuit which is exclusive of selected active elements, to establish an open space for heat dissipation.Type: GrantFiled: September 8, 1987Date of Patent: January 10, 1989Assignee: Mitsubishi Denki, K.K.Inventors: Tadashi Nishimura, Yoichi Akasaka
-
Patent number: 4454166Abstract: A nitride film is formed on a main surface of a semiconductor substrate by plasma CVD process and an oxygen-containing layer is formed on the nitride film and an aluminum-containing film is further formed on the oxygen-containing layer.Type: GrantFiled: January 3, 1983Date of Patent: June 12, 1984Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Haruhiko Abe, Hiroshi Harada, Shigeji Kinoshita, Yoshihiro Hirata, Masahiko Denda, Yoichi Akasaka
-
Patent number: 4448632Abstract: A method of manufacturing a semiconductor device utilizing a monocrystalline silicon layer includes forming and irradiating a polycrystalline silicon layer to increase the grain size thereof, and forming an epitaxial layer thereover. Both layers are then irradiated to convert them into high quality monocrystalline silicon.Type: GrantFiled: May 21, 1982Date of Patent: May 15, 1984Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Yoichi Akasaka
-
Patent number: 4441932Abstract: A process for preparing a semiconductor device having a walled emitter structure covering at least one side surface with a dielectric layer for separation of devices comprises a step of forming a base by implantation of ions with a resist mask for base; a step of forming an emitter by implantation of ions from an emitter-opening part; and a step of formation an active base in a base just below said emitter by implantation of ions from said emitter-opening part.Type: GrantFiled: March 11, 1982Date of Patent: April 10, 1984Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yoichi Akasaka, Katsuhiro Tsukamoto