Systems and methods for amplifying space-multiplexed optical signals
In one embodiment, an optical system for amplifying space-multiplexed optical signals includes an input fiber that propagates multiple spatially-separated optical signals and a bulk amplifier formed of a doped material that receives the multiple spatially-separated optical signals and simultaneously amplifies those signals to generate multiple amplified signals.
1. A space-division multiplexed optical system for amplifying space-multiplexed optical signals, the system comprising:
a multi-mode or multi-core input fiber that propagates multiple spatially-separated optical signals, wherein each of the spatially-separated optical signals comprises a plurality of different wavelengths; and
a bulk amplifier comprising a mass of doped material that receives the multiple wavelength, multiple spatially-separated optical signals and simultaneously amplifies those signals to generate multiple amplified signals, wherein the bulk amplifier comprises no other material.
2. The optical system of claim 1 , further comprising an output fiber that receives the multiple amplified signals from the amplifier.
3. The system of 1 , wherein the input fiber is a multimode fiber, multi-core fiber, or a fiber bundle.
4. The system of 3 , wherein the input fiber is a multi-core fiber having multiple cores and at least one of the cores supports multiple spatial modes.
5. The system of claim 1 , wherein the bulk amplifier is made of phosphate glass.
6. The system of claim 5 , wherein the phosphate glass is doped with erbium or erbium/ytterbium.
7. The system of claim 6 , wherein a doping concentration of the phosphate glass is uniform.
8. The system of claim 6 , wherein a doping concentration of the phosphate glass is non-uniform.
9. The system of claim 1 , further comprising a lens positioned between the input fiber and the bulk amplifier.
10. The system of claim 9 , further comprising an isolator positioned between the lens and the amplifier.
11. The system of claim 9 , further comprising a wedge prism positioned between the input fiber and the lens that tilts off-axis light beams from the fiber.
12. The system of claim 1 , further comprising a microlens that changes the size of the light beams that exit the input fiber.
13. The system of claim 1 , further comprising a pump that pumps the bulk amplifier.
14. The system of claim 13 , wherein the pump is a side pump.
15. The system of claim 13 , wherein the pump is a longitudinal pump.
16. The system of claim 13 , further comprising a reflector that reflects pump energy that is not absorbed by the bulk amplifier back to the bulk amplifier.
17. The system of claim 1 , wherein the bulk amplifier is a doped gradient-index lens.
18. The system of claim 1 , wherein the input fiber has angled output facets that tilt off-axis beams of light as they exit the fiber.
19. The system of claim 1 , further comprising a filter positioned downstream of the bulk amplifier that filters out unused pump light.
20. A space-division multiplexed optical system for amplifying space-multiplexed optical signals, the system comprising:
a multi-core input fiber that comprises multiple cores, each core being configured to propagate a separate optical signal comprises a plurality of different wavelengths;
a doped bulk amplifier comprised of a mass of material that receives the optical signals from the input fiber and simultaneously amplifies those signals to generate multiple amplified signals, wherein the bulk amplifier comprises no other material;
a multi-core output fiber having the same number of cores as the input fiber, wherein each core receives an amplified signal from the amplifier;
a first lens positioned between the input fiber and the bulk amplifier; and
a second lens positioned between the bulk amplifier and the output fiber.
21. The system of claim 20 , wherein the bulk amplifier is made of phosphate glass that is doped with erbium or erbium/ytterbium.
22. The system of claim 20 , further comprising a first isolator positioned between the first lens and the bulk amplifier and a second isolator positioned between the bulk amplifier and the second lens.
23. The system of claim 20 , further comprising a first wedge prism positioned between the input fiber and the first lens and a second wedge prism positioned between the second lens and the output fiber.
24. The system of claim 20 , further comprising a pump that pumps the bulk amplifier.
25. The system of claim 24 , further comprising a reflector that reflects pump energy that is not absorbed by the bulk amplifier back to the bulk amplifier.
26. The system of claim 20 , wherein an output end of the input fiber has angled output facets and an input end of the output fiber has complimentary angled input facets.
27. A method for amplifying space-multiplexed optical signals, the method comprising:
simultaneously amplifying multiple spatially-separated optical signals comprising multiple different wavelengths using a bulk amplifier comprising a mass of doped material, wherein the bulk amplifier comprises no other materials.
28. The method of claim 27 , further comprising delivering the multiple signals to the bulk amplifier using a multimode fiber, multi-core fiber, or a fiber bundle.