LIGHT TRANSMITTER

Japanese Patent JP3275477

B2

PURPOSE: To easily judge a fault by lowering the output of a light amplifier from a normal value or recoverying it from a lowered value to normal when the input light power of the light amplifier or the rear light power of a laser diode becomes less than or more than respective specified values.
CONSTITUTION: Respective threshold value comparing circuits compare the respective output of the rear light monitoring circuit of a laser diode(LD) element of an EGO unit or a light amplifier input light power monitoring circuit connected to a light branching part with respective threshold values. A light output (gain) control circuit which receives signals indicating the result is low or high sets the output or gain of the light amplifier from the normal value to the lowered value or recovers it from the lowered value to the normal value. Thus, this light transmitter does not output unnecessary light when input electric signals are not inputted due to the degradation and fault of the LD element or the connection defect and the fault of a prestage circuit, etc., and is restored when no more fault is present. Thus, in optical fiber communication, the fault is easily judged by using a light power meter.

Yoshiaki Sato
Tomoyoshi Kataoka
Toyoshi Kuwata
Hidetoshi Seki

JP25056893A

April 15, 2002

October 06, 1993

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Nippon Telegraph and Telephone Corporation

H04B10/07; H04B10/079; H04B10/2507; H04B10/293; H04B10/40; H04B10/50; H04B10/564; H04B10/60; (IPC1-7): H04B10/08; H04B10/04; H04B10/06; H04B10/14; H04B10/26; H04B10/28

JP2266245A
JP5130043A
JP63257343A
JP2305042A
JP4188686A
JP5129695A
JP4293024A
JP4132428A
JP3105050U

Akihide Sugimura (1 outside)

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