Gain clamped thulium-doped fiber amplification
View Patent ↗An optical amplifier system is disclosed comprising a Thulium-doped fiber span, a pump system, and a feedback loop. The Thulium-doped fiber span receives input optical signals. The pump system pumps light having a wavelength in the range of 1049 nm to 1060 nm onto the Thulium-doped fiber span. The light amplifies the input optical signals to generate amplified optical signals. The Thulium-doped fiber span transfers the amplified optical signals. The feedback loop receives at least one wavelength of amplified emissions from the Thulium-doped fiber span. The feedback loop generates optical feedback signals based the wavelength or wavelengths of the amplified emissions. The feedback loop adds the optical feedback signals to the input optical signals to provide clamping of a gain in the amplified optical signals.
1. 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.
2. The optical amplifier system of claim 1 wherein the Thulium-doped fiber span comprises a Fluoride-based Thulium-doped fiber span.
3. The optical amplifier system of claim 1 wherein the Thulium-doped fiber span has a length of about 20 meters.
4. The optical amplifier system of claim 1 wherein the pump system is configured to amplify the S-band of the input optical signals.
5. The optical amplifier system of claim 1 wherein the pump system is configured to forward pump the light onto the Thulium-doped fiber span.
6. The optical amplifier system of claim 1 wherein the pump system comprises an Ytterbium fiber laser.
7. The optical amplifier system of claim 1 wherein the pump system is configured to pump the light having a wavelength of about 1050 nm onto the Thulium-doped fiber span.
8. The optical amplifier system of claim 1 wherein the feedback loop comprises:
a variable attenuator configured to receive the at least one wavelength of the amplified emissions and control a degree of clamping of the gain in the amplified optical signals by attenuating the at least one wavelength of the amplified emissions to generate the optical feedback signals.
9. The optical amplifier system of claim 1 wherein the gain generated by the optical amplifier system is shifted to longer wavelengths.
10. The optical amplifier system of claim 1 wherein a wavelength range of the gain clamped by the optical amplifier system is greater than 10 nm.
11. A method of operating an optical amplifier system comprised of a Thulium-doped fiber span, a pump system, and a feedback loop, the method comprising the steps of:
receiving input optical signals into the Thulium-doped fiber span;
pumping light having a wavelength in the range of 1049 nm to 1060 nm onto the Thulium-doped fiber span with the pump system to amplify the input optical signals to generate amplified optical signals;
transferring the amplified optical signals from the Thulium-doped fiber span;
receiving at least one wavelength of amplified emissions from the Thulium-doped fiber span onto the feedback loop, wherein the at least one wavelength of the amplified emissions does not overlap with a wavelength of the input optical signals;
generating optical feedback signals based on the at least one wavelength of the amplified emissions in the feedback loop;
adding the optical feedback signal to the input optical signals in the feedback loop to provide clamping of a gain in the amplified optical signals; and
preventing optical signals from traveling into the Thulium-doped fiber span against a direction of the input optical signals.
12. The method of claim 11 wherein the Thulium-doped fiber span comprises a Fluoride-based Thulium-doped fiber span.
13. The method of claim 11 wherein the Thulium-doped fiber span has a length of about 20 meters.
14. The method of claim 11 wherein the step of pumping light onto the Thulium-doped fiber span with the pump system to amplify the input optical signals comprises:
pumping the light onto the Thulium-based fiber span to amplify the S-band of the input optical signals.
15. The method of claim 11 wherein the step of pumping light onto the Thulium-doped fiber span comprises:
forward pumping the light onto the Thulium-doped fiber span.
16. The method of claim 11 wherein the pump system comprises an Ytterbium fiber laser.
17. The method of claim 11 wherein the step of pumping light onto the Thulium-doped fiber span comprises:
pumping the light having a wavelength of about 1050 nm onto the Thulium-doped fiber span.
18. The method of claim 11 wherein the feedback loop includes a variable attenuator and wherein the method further comprises the steps of:
receiving the at least one wavelength of the amplified emissions into the variable attenuator; and
controlling a degree of clamping of the gain in the amplified optical signals by attenuating the at least one wavelength of the amplified emissions to generate the optical feedback signals in the variable attenuator.
19. The method of claim 11 wherein the gain generated by the optical amplifier system is shifted to longer wavelengths.
20. The method of claim 11 wherein a wavelength range of the gain clamped by the optical amplifier system is greater than 10 nm.