| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical transmission system that prevents an optical signal of an unstable level from being transmitted through each node, so as to enhance the rising state of the WDM at initialization thereby enhancing transmission quality. <P>SOLUTION: An optical preamplifier 11 has an ALC function for controlling an optical output level to be constant and an AGC function for making the gain constant, and transits to an AGC mode after the optical preamplifier 11 sets the gain in an ALC mode. An optical post-amplifier 12 has an AGC function. An optical switch section 13 performs optical cross connect control. A through-light interruption control section 14a sets its switch to shut off the through-light of an optical switch section 13 when the optical preamplifier 11 is set to the ALC mode, so as to avoid an optical signal of an unstable level from being transmitted to a next stage and releases the interruption of the through-light when the optical preamplifier 11 transits to the AGC mode. Optical transmission media F interconnect a plurality of nodes 10a-1 to 10a-4. <P>COPYRIGHT: (C)2004,JPO |
