Patent ID: 6950232

Claim:
An optical amplifier system, comprising: A Thulium-doped fiber span configured to receive input optical signals and transfer amplified optical signals; a pump system coupled to the Thulium-doped fiber span and configured to pump light having a wavelength in the range of 1049 nm to 1060 nm onto the Thulium-doped fiber span to amplify the input optical signals to generate the amplified optical signals; a feedback loop configured to receive at least one wavelength of amplified emissions from the Thulium-doped fiber span, generate optical feedback signals based on the at least one wavelength of the amplified emissions, and add the optical feedback signals to the input optical signals to provide clamping of a gain in the amplified optical signals; and an optical isolator configured to prevent optical signals from traveling into the Thulium-doped fiber span against a direction of the input optical signals; wherein the at least one wavelength of the amplified emissions does not overlap with a wavelength of the input optical signals.