OPTICAL AMPLIFIER

Japanese Patent JP2725109

B2

PURPOSE: To decide the deterioration of a laser for excitation light generation by also referring to an output signal level in an optical amplifier using a light amplification fiber.
CONSTITUTION: The optical amplification fiber 1 is equipped with a laser 2 in current use and a spare laser 3 to add excitation light via optical couplers 9a, 9b, a signal light monitoring part 4 which monitors by branching the output signal light of the optical amplification fiber 1 partially, and a driving current monitoring part 5 which monitors the driving current of the laser 2 in current use by a driving circuit 7. Also, it is equipped with a monitor control part 6 which decides that the deterioration of the laser 2 in current use occurs, or a fault occurs in the driving circuit 7 of the laser 2 in current use and generates the excitation light by switching the laser from the laser 2 in current use to the spare laser 3 when the monitor output signal of the driving current monitoring part 5 is increased/decreased exceeding over a prescribed range and also, the monitor output signal of the signal light monitoring part 4 is decreased less than a prescribed value.

JP2931694	INDUSTRIAL APPLICABILITY [Title of Invention] Optical Functional Glass
JPH03260635	FORMATION OF PARTIAL POLARIZATION INVERSION REGION
JP2845403	[Title of Invention] Optical coupling device for optical communication device

HARASAWA SHINICHIRO

JP4946492A

March 09, 1998

March 06, 1992

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FUJITSU KK

G02F1/35; H01S3/06; H01S3/067; H01S3/07; H01S3/094; H01S3/0941; H01S3/13; H04B10/032; H04B10/079; H04B10/29; H04B10/293; H01S3/131; (IPC1-7): H04B10/17; H01S3/13; H04B10/16

JP43029A
JP3252232A
JP4165334A
JP465175A
JP5190946A

Shoji Kashiwaya (1 person outside)

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