An optical transmission device has an optical amplifier, first and second control
signal reception units and a transmission unit. The first control signal reception
unit receives control signals from a receiving end optical service channel. The
second control signal reception unit receives control signals from an operator.
The transmission unit transmits to the optical amplifier, either the control signals
from the receiving end optical service channel or the control signals from the
operator so that the optical amplifier operates in either an automatic level control
mode or an automatic gain control mode.
