Patent ID: 7038841
Filing Date: 2006-05-02
Classification: H01S,H04B

Abstract:
1. A fiber amplifier comprising: a first stage amplifier including a first fiber and a first pump laser diode, the first stage amplifier amplifying an input light by a predetermined gain; a second stage amplifier including a second fiber and a second pump laser diode, the second stage amplifier receiving an output light of the first stage amplifier and generating a Raman gain; a third stage amplifier including a third fiber and a third pump laser diode, the third stage amplifier amplifying the light output from the second stage amplifier by a predetermined gain; and an automatic gain controller configured for receiving part of the light input to the first stage amplifier to check whether an input light power is varied, and when the input light power is varied, controlling pump powers of the second and third pump laser diodes respectively of the second and third stage amplifiers to obtain a constant gain, the pump powers of the second and third pump laser diodes being controlled in a state where a pump light of the first pump laser diode of the first stage amplifier is fixed.