| US 7,586,672 B2 | ||
| Optical transmission system | ||
| Eiji Ishikawa, Hokkaido (Japan); Hiroto Ikeda, Hokkaido (Japan); and Hiroyuki Deguchi, Kawasaki (Japan) | ||
| Assigned to Fujitsu Limited, Kawasaki (Japan) | ||
| Filed on Jun. 12, 2007, as Appl. No. 11/808,754. | ||
| Application 11/808754 is a division of application No. 10/635732, filed on Aug. 07, 2003, granted, now 7,251,072. | ||
| Claims priority of application No. 2002-246127 (JP), filed on Aug. 27, 2002. | ||
| Prior Publication US 2007/0242347 A1, Oct. 18, 2007 | ||
| Int. Cl. H04B 10/17 (2006.01); H04B 10/12 (2006.01) | ||
| U.S. Cl. 359—334 [359/341.3; 359/341.31] | 2 Claims |
| 1. An optical transmission system comprising:
(a) an optical transmitter comprising:
an optical amplifier that amplifies main optical signals for transport over a downstream fiber-optic transmission line, and
an optical amplifier controller that raises output power of said optical amplifier up to a desired level in a stepwise fashion;
and
(b) an optical receiver comprising:
a pump light source that produces a pump light to the upstream fiber-optic transmission line so as to cause Raman amplification,
a pump light source controller that raises a level of the pump light to a desired power level in a stepwise fashion, and
a monitoring controller that monitors power levels of at least one of incoming main optical signals and an incoming optical
supervisory signal;
wherein the number and interval of steps in the stepwise raising of the pump light are determined based on the monitoring
result.
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