Abstract: The invention relates to a regulatable optical amplifier which has at least two series-connected amplifier groups, each amplifier group having a regulating device. Connected upstream of the optical amplifier is a power monitor device for detecting changes in the input power, whose electrical output is connected both to the first regulating device and to the second regulating device. In line with the invention, the first and second regulating devices have a control line inserted between them which comprises a series circuit containing a high-pass filter, a delay and signal-shaping unit and a feed-forward control unit for generating a correction signal for the second regulating device. In this arrangement, the high-pass filter has a cut-off frequency which corresponds approximately to the cut-off frequency of the first amplifier group.

Abstract: The invention relates to a regulatable optical amplifier which has at least two series-connected amplifier groups, each amplifier group having a regulating device. Connected upstream of the optical amplifier is a power monitor device for detecting changes in the input power, whose electrical output is connected both to the first regulating device and to the second regulating device. In line with the invention, the first and second regulating devices have a control line inserted between them which comprises a series circuit containing a high-pass filter, a delay and signal-shaping unit and a feed-forward control unit for generating a correction signal for the second regulating device. In this arrangement, the high-pass filter has a cut-off frequency which corresponds approximately to the cut-off frequency of the first amplifier group.

Abstract: A gain control circuit for an optical amplifier includes a feed-forward path which enables the pump power of an excitation laser to be controlled based on input power of the amplifier. The feed-forward path is complemented by a feed-back loop which includes: a subtractor that outputs an error signal based on a difference between scaled input power and output power of the optical amplifier; a regulator which generates a bias and correction signal that reduces the error signal to zero; and an adder which adds the bias and correction signal to the input power signal of the feed-forward path. The output of the adder forms a pump control signal which maintains a desired gain of the amplifier irrespective of fluctuations in input power and channel load changes, as well as other influences. Through the use of purely electronic control, the control circuit controls the gain of the amplifier with substantially less pump power than conventional circuits utilizing other known methods.

Abstract: A gain control circuit for an optical amplifier includes a feed-forward path which enables the pump power of an excitation laser to be controlled based on input power of the amplifier. The feed-forward path is complemented by a feed-back loop which includes: a subtractor that outputs an error signal based on a difference between scaled input power and output power of the optical amplifier; a regulator which generates a bias and correction signal that reduces the error signal to zero; and an adder which adds the bias and correcction signal to the input power signal of the feed-forward path. The output of the adder forms a pump control signal which maintains a desired gain of the amplifier irrespective of fluctuations in input power and channel load changes, as well as other influences. Through the use of purely electronic control, the control circuit controls the gain of the amplifier with substantially less pump power than conventional circuits utilizing other known methods.