| 摘要 |
PROBLEM TO BE SOLVED: To perform a fixed controlling of the gain, according to gain by controlling an optical amplifier, based on the previously set gain, and to perform optical transmission of high flexibility. SOLUTION: The fixed control of the gain according to user's needs is performed in the optical amplifier 40 by controlling an attenuation of an optical variable attenuator 43 so that the total gain of optical fiber amplifying sections 41, 42, 50 including a DCF 56 becomes a predetermined gain previously set by users or the like. Moreover, the previously set gain of the optical amplifier 40 is also given to AGC circuits 44, 51, and the gains of the optical fiber amplifying sections 41, 42, 50 are controlled so as to reach this gain. COPYRIGHT: (C)2006,JPO&NCIPI |
