Inventor · disambiguated record
Tohru Kazawa
Also filed as: KAZAWA TOHRU
65 granted patents·2 pending applications·894 citations·filing 1987–2012
99Inventor score
Top patents by PatentIndex Score
67 records- 0197US7675936B2Passive optical network (PON) systemHITACHI LTD·Filed 2006·Granted Mar 9, 2010·73 cites·9 claims
- 0295US7873277B2Passive optical network system and wavelength assignment methodHITACHI LTD·Filed 2007·Granted Jan 18, 2011·27 cites·9 claims
- 0395US5500756AOptical fiber transmission system and supervision method of the sameHITACHI LTD·Filed 1993·Granted Mar 19, 1996·183 cites·13 claims
- 0494US7630637B2PON system and optical network unitHITACHI COMM TECH LTD·Filed 2006·Granted Dec 8, 2009·20 cites·6 claims
- 0592US7548694B2Apparatus of adjusting optical signal transmission timingHITACHI COMM TECH LTD·Filed 2007·Granted Jun 16, 2009·15 cites·11 claims
- 0691US8036532B2Passive optical network system, optical line terminal, and optical network unitHITACHI LTD·Filed 2010·Granted Oct 11, 2011·9 cites·25 claims
- 0791US7620325B2Transmission apparatus with function of multi-step bandwidth assignment to other communication apparatusesHITACHI COMM TECH LTD·Filed 2006·Granted Nov 17, 2009·28 cites·3 claims
- 0890US8811819B2Optical multiplexing terminal device, wavelength multiplexing passive optical network system and downlink wavelength transmission methodKAZAWA TOHRU·Filed 2009·Granted Aug 19, 2014·16 cites·7 claims
- 0990US7734178B2Passive optical network system, optical line terminal, and optical network unitHITACHI LTD·Filed 2007·Granted Jun 8, 2010·13 cites·28 claims
- 1090US7483506B2Bit synchronization circuit with phase tracking functionHITACHI COMM TECH LTD·Filed 2005·Granted Jan 27, 2009·18 cites·13 claims
- 1190US7369768B2Optical access systemHITACHI COMM TECH LTD·Filed 2006·Granted May 6, 2008·12 cites·21 claims
- 1288US7680414B2Passive optical network system and operating method thereofHITACHI LTD·Filed 2007·Granted Mar 16, 2010·13 cites·1 claims
- 1387US8457492B2Optical access systemOHIRA MASAKI·Filed 2010·Granted Jun 4, 2013·13 cites·11 claims
- 1486US8712244B2Communication system and time synchronization methodHASEGAWA MAKOTO·Filed 2011·Granted Apr 29, 2014·10 cites·14 claims
- 1586US8249454B2Optical communication system and optical line terminating apparatusSUGAWARA TOSHIKI·Filed 2009·Granted Aug 21, 2012·15 cites·11 claims
- 1686US8184977B2Optical line terminal capable of active bandwidth allocation for passive optical network systemKAZAWA TOHRU·Filed 2010·Granted May 22, 2012·6 cites·4 claims
- 1786US7889990B2Optical line terminal capable of active bandwidth allocation for passive optical network systemHITACHI LTD·Filed 2007·Granted Feb 15, 2011·11 cites·8 claims
- 1885US8139950B2Passive optical network system, optical line terminator and, communication method of passive optical network systemNIIBE MASAO·Filed 2008·Granted Mar 20, 2012·15 cites·11 claims
- 1985US7725031B2Passive optical network system and ranging system thereofHITACHI LTD·Filed 2008·Granted May 25, 2010·7 cites·7 claims
- 2085US7489869B2Passive optical network system and ranging system thereofHITACHI COMM TECH LTD·Filed 2007·Granted Feb 10, 2009·7 cites·4 claims
- 2184US8705965B2Method of recovery from sleep state of an ONU in a PON system capable of power savingSUGAWA JUN·Filed 2011·Granted Apr 22, 2014·8 cites·10 claims
- 2284US8260135B2Passive optical network system and wavelength assignment methodKAZAWA TOHRU·Filed 2010·Granted Sep 4, 2012·6 cites·4 claims
- 2384US8107824B2Passive optical network system and communication method thereforTSUCHIYA AKIHIKO·Filed 2008·Granted Jan 31, 2012·13 cites·3 claims
- 2483US8861954B2Burst-mode receiver equipped with optical amplifier, method for controlling optical amplifier, and systemSUGAWA JUN·Filed 2011·Granted Oct 14, 2014·7 cites·19 claims
- 2582US7957647B2Passive optical network system and ranging methodHITACHI LTD·Filed 2008·Granted Jun 7, 2011·9 cites·11 claims
- 2682US7773880B2Optical access systemHITACHI LTD·Filed 2008·Granted Aug 10, 2010·6 cites·8 claims
- 2782US7239813B2Bit synchronization circuit and central terminal for PON systemsHITACHI COMM TECH LTD·Filed 2003·Granted Jul 3, 2007·24 cites·4 claims
- 2881US8374504B2Optical communication systemHITACHI LTD·Filed 2006·Granted Feb 12, 2013·8 cites·11 claims
- 2980US8948595B2Passive optical network system, optical line terminal, and optical network unitHITACHI LTD·Filed 2012·Granted Feb 3, 2015·8 cites·9 claims
- 3080US8145055B2Passive optical network system, optical line terminator and optical network unitNIIBE MASAO·Filed 2009·Granted Mar 27, 2012·8 cites·13 claims
- 3180US8023511B2Communication system, optical line terminal, and congestion control methodHITACHI LTD·Filed 2009·Granted Sep 20, 2011·13 cites·10 claims
- 3280US7711268B2Passive optical network system and ranging system thereofHITACHI LTD·Filed 2008·Granted May 4, 2010·5 cites·7 claims
- 3379US8005362B2Passive optical network system and optical line terminalHITACHI LTD·Filed 2008·Granted Aug 23, 2011·6 cites·3 claims
- 3478US8477800B2Passive optical network system and operation method thereofKAZAWA TOHRU·Filed 2010·Granted Jul 2, 2013·5 cites·9 claims
- 3577US7512341B2Passive optical network system and ranging system thereofHITACHI COMM TECH LTD·Filed 2008·Granted Mar 31, 2009·4 cites·3 claims
- 3677US5424882ASignal processor for discriminating recording dataHITACHI LTD·Filed 1993·Granted Jun 13, 1995·24 cites·4 claims
- 3776US7840137B2Optical line terminal and optical network unit capable of alarm transmission scheme for passive optical network systemHITACHI LTD·Filed 2007·Granted Nov 23, 2010·6 cites·6 claims
- 3876US5237590ATiming extraction circuit and communication system utilizing the sameHITACHI LTD·Filed 1991·Granted Aug 17, 1993·42 cites·12 claims
- 3975US7962037B2PON system and optical network unitHITACHI LTD·Filed 2009·Granted Jun 14, 2011·4 cites·18 claims
- 4073US8249455B2Passive optical network system and ranging methodKAZAWA TOHRU·Filed 2011·Granted Aug 21, 2012·3 cites·8 claims
- 4173US7908390B2Packet forwarding apparatus using token bucket algorithm and leaky bucket algorithmHITACHI LTD·Filed 2006·Granted Mar 15, 2011·5 cites·28 claims
- 4272US8467684B2Apparatus of adjusting optical signal transmission timingKAZAWA TOHRU·Filed 2011·Granted Jun 18, 2013·2 cites·7 claims
- 4372US8090261B2Network system, optical line terminating apparatus, and optical network apparatusSUGAWARA TOSHIKI·Filed 2008·Granted Jan 3, 2012·5 cites·34 claims
- 4471US8184976B2Passive optical network system and operating method thereofKAZAWA TOHRU·Filed 2009·Granted May 22, 2012·4 cites·5 claims
- 4571US7676127B2Optical communication system using WDMA and CDMAHITACHI COMM TECH LTD·Filed 2007·Granted Mar 9, 2010·3 cites·13 claims
- 4671US5434886ADigital communication systemHITACHI LTD·Filed 1993·Granted Jul 18, 1995·60 cites·7 claims
- 4768US8724995B2Passive optical network system and operating method thereofKAZAWA TOHRU·Filed 2009·Granted May 13, 2014·3 cites·7 claims
- 4868US8532491B2Optical multiplexing terminating device, passive optical network system and method for allocating wavelengthSAKAMOTO NORIHIRO·Filed 2009·Granted Sep 10, 2013·4 cites·6 claims
- 4968US8204168B2Bit synchronization circuit with phase tracking functionYAJIMA YUSUKE·Filed 2009·Granted Jun 19, 2012·4 cites·9 claims
- 5067US8886041B2Optical line terminal, bandwidth control method and optical network systemTANAKA TAKAHIRO·Filed 2012·Granted Nov 11, 2014·2 cites·13 claims
Showing the top 50 of 67 patent records by PatentIndex Score.
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Identity basis: PatentsView inventor disambiguation (2025Q4-odp release). How scoring works →