Patent ID: 8873135

Claim:
An extended dynamic range optical amplifier, comprising: a first gain stage configured to receive an input signal; a first optical switch configured to receive an output of the first gain stage and to switch the output of the first gain stage to one of a first output and a second output; a second gain stage connected to the first output and configured to receive the output of the first gain stage based on a configuration of the first optical switch; a second optical switch comprising a first input connected to an output of the second gain stage and a second input connected to the second output of the first optical switch, wherein the second optical switch is configured to provide a single output; a third gain stage configured to receive the single output from the second optical switch; and control circuitry configured to control operation of the first optical switch, the second optical switch, the first gain stage, the second gain stage, and the third gain stage; wherein the control circuitry is configured to set the first optical switch and the second optical switch such that the second gain stage is in line with the first gain stage and the third gain stage in a high gain mode of operation and to set the first optical switch and the second optical switch such that the second gain stage is out of line with the first gain stage and the third gain stage in a low gain mode of operation, and wherein the control circuitry is further configured to, responsive to operation in the low gain mode of operation in a cooperative manner with a Raman amplifier, detect a failure of the Raman amplifier and, responsive to the failure of the Raman amplifier, switch to the high gain mode of operation.