Patent ID: 6650467
Filing Date: 2003-11-18
Classification: H01S

Abstract:
An erbium-doped optical fiber amplifier using input optical signal filtering, comprising:a first amplification stage for receiving an input optical signal and first forward and backward excitation light, and amplifying the input optical signal using energy released when erbium ions excited by the excitation light return to their original energy level; a pre-processing means for performing a gain equalization process and a light intensity attenuating process for the signal amplified in said first amplification stage; a second amplification stage for receiving the optical signal processed in said pre-processing means and second forward and backward excitation light and performing a second amplification operation; a plurality of laser diodes for generating the first and second forward and backward excitation light and providing the first and second forward and backward excitation light to said first and second amplification stages, respectively; an input optical signal detector for branching and receiving some of the input optical signal, separating the received optical signal into two signals having a ratio of 50:50, and photo-electrically converting a first one of the separated optical signals by performing a filtering process for compensating for the gain inhomogeneity characteristics of the fiber, and a second one without any filtering; and a laser diode controller for generating forward diode control voltage of said first amplification stage using the filtered signal of the electrical signals provided by said input optical signal detector and generating other laser diode control voltage using the signal that is not filtered.