Patent ID: 7773886

Claim:
An optical fiber transmission system comprising an optical transmitter, an optical receiver, an optical fiber to connect the transmitter with the receiver, a plurality of optical amplifiers along the optical fiber to compensate absorption losses of a signal light passing through the optical fiber, and at least one optical regenerator, wherein the optical regenerator including: an optical amplifier at an input of the regenerator; an all-optical nonlinear device to provide a nonlinear transfer function between optical input power of an optical signal after the optical amplifier and optical output power of an optical signal after the nonlinear device; an adjusting device to receive the optical signal after the nonlinear device, adjust the optical output power of the optical signal after the nonlinear device to a level of launch power from the regenerator, and output an adjusted optical signal; a first monitoring device including a photodiode to measure the optical input power of the optical signal after the optical amplifier and output a first monitoring signal; a second monitoring device to monitor an optical signal after the adjusting device and output a second monitoring signal; and a control unit to receive the first and second monitoring signals, control the optical amplifier based on the first monitoring signal to adjust an optical input power to the nonlinear device to a preset value, control the adjusting device based on the second monitoring signal, and communicate with one of another optical regenerator and a receiver via an optical supervisory channel, wherein a target value of an average input power to the nonlinear device detected by the photodiode is set as the preset value at a time of installation of the regenerator in the optical fiber transmission system, wherein the optical input power to the nonlinear device of each regenerator is adjusted such that a bit error rate at the receiver is minimized and an adjusted value is stored as the target value at the time of installation, wherein a procedure of setting the target value is performed in backward direction starting from a regenerator closest to the receiver, and wherein the optical supervisory channel is used for communication between a location of the receiver and each regenerator.