Patent ID: 8102595

Claim:
An optical transmission system for transmitting light through an optical fiber transmission line, comprising: an upstream station including a first optical amplifier; and a downstream station including a second optical amplifier, and a controller configured to determine a gain of the second optical amplifier when setting up the second optical amplifier, wherein an optical loss medium having a loss characteristic not uniform in a direction of wavelength is arranged at a stage preceding the second optical amplifier, and the controller acquires a noise light loss value, which indicates a loss that noise light output from the first optical amplifier of the upstream station undergoes during propagation to the second optical amplifier through the optical loss medium, and a signal beam loss value, which indicates a loss that a signal beam output from the first optical amplifier undergoes during propagation to the second optical amplifier through the optical loss medium, obtains, as a loss difference, a difference between the noise light loss value and the signal beam loss value and, when setting up the second optical amplifier, determines the gain by compensating the loss difference.