| 摘要 |
PROBLEM TO BE SOLVED: To solve the conventional problem of difficulty in controlling an optical amplifier gain according to the distance of a transmission line.SOLUTION: An optical transmission device includes: an optical amplifier for amplifying an optical signal; a splitter for splitting transmission light output by the optical amplifier to an optical transmission line from return light returning from the optical transmission line on the basis of the transmission light; and a control circuit for monitoring the signal level of the return light split by the splitter, and for controlling an optical amplifier gain according to the distance of the transmission line estimated from the signal level. |
