Inventor
MATSUMOTO KEIICHI
JP24 patents
⚠️ This page may combine multiple inventors who share the name “MATSUMOTO KEIICHI”. Patents are grouped by organization below to help distinguish them — per-person disambiguation is on the roadmap.
NEC CORP
14 patentsUS12555971B2Feb 17, 2026
Light amplification device, light transmission system, and light amplification method
NEC CORP0 citations62
US12512642B2Dec 30, 2025
Monitoring device, monitoring method, optical amplifier, and optical transmission system
NEC CORP0 citations62
US12308599B2May 20, 2025
Optical amplifier, optical amplifier equalizing method, and transmission system
NEC CORP0 citations62
US12072243B2Aug 27, 2024
Monitoring device, monitoring method, and optical transmission system
NEC CORP0 citations62
US11881675B2Jan 23, 2024
Optical amplification device, optical transmission system, and optical amplification method
NEC CORP0 citations62
US11374377B2Jun 28, 2022
Optical amplifying apparatus and method of amplifying optical signal
NEC CORP0 citations62
US11870208B2Jan 9, 2024
Optical fiber amplifier, optical fiber amplifier control method, and transmission system
NEC CORP0 citations59
US12375201B2Jul 29, 2025
Optical amplifier, optical amplifier controlling method, and optical transmission system
NEC CORP0 citations52
US12374851B2Jul 29, 2025
Optical amplification apparatus and optical amplification method
NEC CORP0 citations52
US12027813B2Jul 2, 2024
Optical amplifier and optical amplification method
NEC CORP0 citations52
US11990727B2May 21, 2024
Monitoring apparatus for optical amplifier, optical amplifying system, and method of monitoring amplified optical signal
NEC CORP0 citations51
US11876339B2Jan 16, 2024
Optical amplifier, control method for optical amplifier, and optical communication system
NEC CORP0 citations51
US11683116B2Jun 20, 2023
Light amplification device, light transmission system, and light amplification method
NEC CORP0 citations51
US11329444B2May 10, 2022
Optical amplifier and control method therefor
NEC CORP0 citations51
PIONEER ELECTRONIC CORP
6 patentsUS4722079AJan 26, 1988
Optical disk player capable of distinguishing external disturbances and local defects and adjusting servo gain accordingly
PIONEER ELECTRONIC CORP36 citations92
US4748608AMay 31, 1988
Servo apparatus for tracking and rotational speed control
PIONEER ELECTRONIC CORP22 citations82
US4701902AOct 20, 1987
Automatic loading disc player
PIONEER ELECTRONIC CORP20 citations81
US4879705ANov 7, 1989
Automatic loading disc player
PIONEER ELECTRONIC CORP15 citations73
US4829502AMay 9, 1989
Automatic loading disc player
PIONEER ELECTRONIC CORP12 citations73
US4544872AOct 1, 1985
Tracking servo control system for an information read-out system
PIONEER ELECTRONIC CORP18 citations73