Inventor
TSUSHIMA HIDEAKI
JP37 patents
⚠️ This page may combine multiple inventors who share the name “TSUSHIMA HIDEAKI”. Patents are grouped by organization below to help distinguish them — per-person disambiguation is on the roadmap.
HITACHI LTD
32 patentsUS5500756AMar 19, 1996
Optical fiber transmission system and supervision method of the same
HITACHI LTD183 citations97
US5396361AMar 7, 1995
Frequency separation stabilization method for optical heterodyne or optical homodyne communication
HITACHI LTD59 citations96
US5323258AJun 21, 1994
Homodyne optical receiver equipment
HITACHI LTD84 citations96
US5305134AApr 19, 1994
Optical frequency division multiplexing transmitter and optical frequency division multiplexing transmission apparatus
HITACHI LTD57 citations96
US5274490ADec 28, 1993
Optical transmitter, optical receiver and optical transmission apparatus and control method of optical receiver
HITACHI LTD30 citations93
US5023950AJun 11, 1991
Optical transmitter, optical receiver and optical transmission apparatus and control method of optical receiver
HITACHI LTD22 citations93
US6933852B2Aug 23, 2005
Optical switching apparatus and optical communication network system
HITACHI LTD18 citations92
US6424445B1Jul 23, 2002
Optical transmission apparatus and optical systems
HITACHI LTD26 citations92
US6341032B1Jan 22, 2002
Method and system for reducing optical surge
HITACHI LTD24 citations92
US5422968AJun 6, 1995
Optical demultiplexing system with optical amplifiers
HITACHI LTD26 citations92
US5408349AApr 18, 1995
Optical frequency division multiplexing transmission system
HITACHI LTD54 citations92
US5144467ASep 1, 1992
Optical tuning method and apparatus suitable for selective reception of optical frequency division multiplex signals
HITACHI LTD26 citations92
US5140453AAug 18, 1992
Optical receiving method utilizing polarization diversity and apparatus for carrying out the same
HITACHI LTD32 citations92
US5113524AMay 12, 1992
Quantum state control apparatus, optical receiver and optical communication system
HITACHI LTD40 citations92
US4909584AMar 20, 1990
Optical multi/demultiplexer and optical module using the same
HITACHI LTD34 citations92
US6304346B1Oct 16, 2001
Fault restoration control method and it's apparatus in a communication network
HITACHI LTD18 citations84
US6975811B1Dec 13, 2005
Optical one-to-one protection switching apparatus
HITACHI LTD15 citations83
US7302176B2Nov 27, 2007
Optical network
HITACHI LTD12 citations82
US5142402AAug 25, 1992
Polarization diversity optical receiving apparatus and method
HITACHI LTD20 citations82
US6731874B2May 4, 2004
Optical transmission apparatus and optical systems
HITACHI LTD6 citations74
US6839480B2Jan 4, 2005
Optical switching apparatus, optical transmission system and method of setting up for optical signal route
HITACHI LTD6 citations73
US6778725B1Aug 17, 2004
Optical switching apparatus, optical transmission system and method of setting up for optical signal route
HITACHI LTD9 citations73
US10020982B2Jul 10, 2018
Failure isolation method and management server for failure isolation
HITACHI LTD5 citations72
US6434286B2Aug 13, 2002
Optical signal switching apparatus
HITACHI LTD12 citations72
US6229932B1May 8, 2001
Optical signal switching apparatus
HITACHI LTD12 citations71
US6970614B2Nov 29, 2005
Optical switching equipment, optical transport network, and methods of using them
HITACHI LTD3 citations63
US7356257B2Apr 8, 2008
Optical switching apparatus and optical communication network system
HITACHI LTD4 citations62
US7206475B2Apr 17, 2007
Optical switching apparatus, optical transmission system and method of setting up for optical signal route
HITACHI LTD2 citations62
US6463191B1Oct 8, 2002
Optical switching device and optical switching method
HITACHI LTD4 citations62
US7194205B2Mar 20, 2007
Optical transmission apparatus and optical systems
HITACHI LTD0 citations52
US6334009B1Dec 25, 2001
Optical signal switching apparatus
HITACHI LTD0 citations49
US6577784B2Jun 10, 2003
Optical switch
HITACHI LTD0 citations48