Apparatus, system and method for an adiabatic coupler for multi-mode fiber-optic transmission systems
View Patent ↗An improved fiber-optic communications system comprises a multi-mode waveguide carrying an optical signal, a single-mode waveguide optically coupled to and receiving the optical signal from the multi-mode waveguide and an adiabatic coupler optically coupled between the multi-mode waveguide and the single-mode waveguide. The multi-mode and single-mode waveguides may be optical fibers. The adiabatic coupler may comprise a tapered core surrounded by a cladding. Alternatively, the adiabatic coupler may comprise a core surrounded by a cladding, wherein the refractive index of at least one of the core and the cladding varies over the length of the adiabatic coupler.
1. An optical module, comprising:
an optical device;
an adiabatic coupler optically coupled to the optical device, wherein the adiabatic coupler is configured to enable a fundamental mode of light to propagate adiabatically therethrough, the adiabatic coupler having a core with a constant diameter from a first end to a second end and a cladding surrounding the core, wherein the cladding has a refractive index that varies from the first end to the second end; and
an optical connector affixed to the adiabatic coupler.
2. The optical module of claim 1 , wherein the optical device is a transmitter.
3. The optical module of claim 1 , wherein the optical device is a receiver.
4. The optical module of claim 1 , further comprising a single-mode fiber optically coupled between the optical device and the adiabatic coupler.
5. The optical module of claim 1 , wherein the variation of the refractive index is such that a mode field at the first end of the core substantially matches a mode field of the multi-mode fiber and a mode field at the second end of the core substantially matches a mode field of the single-mode fiber.
6. A fiber-optic communications system, comprising:
a multi-mode fiber having a first end and a second end;
a first single-mode fiber;
a first adiabatic coupler optically coupled to the first end of the multi-mode fiber and to one end of the single-mode fiber, wherein the adiabatic coupler is configured to enable a fundamental mode of light to propagate adiabatically between the multi-mode fiber and the single-mode fiber;
a second single-mode fiber; and
a second adiabatic coupler optically coupled to the second end of the multi-mode fiber and to one end of the second single-mode fiber, wherein at least one adiabatic coupler includes a core having a first end and a second end and a cladding surrounding the core, wherein one of the core or the cladding has a refractive index that varies from the first end to the second end.
7. The fiber-optic communications system of claim 6 , wherein at least one adiabatic coupler includes a tapered core having a first end with a first diameter and a second end with a second diameter, wherein the first diameter is greater than the second diameter.
8. The fiber-optic communications system of claim 7 , wherein the first diameter is sized such that a mode field at the first end of the tapered core substantially matches a mode field of the multi-mode fiber, and the second diameter is sized such that a mode field at the second end of the tapered core substantially matches a mode field of the single-mode fiber.
9. The fiber-optic communications system of claim 8 , wherein the light is transmitted from the multi-mode fiber to the single-mode fiber.
10. The fiber-optic communications system of claim 8 , wherein the light is transmitted from the single-mode fiber to the multi-mode fiber.
11. The fiber-optic communications system of claim 6 , wherein the variation of the refractive index is such that a mode field at the first end of the core substantially matches a mode field of the multi-mode fiber and a mode field at the second end of the core substantially matches a mode field of the single-mode fiber.
12. The fiber-optic communications system of claim 11 , wherein the light is transmitted from the multi-mode fiber to the single-mode fiber.
13. The fiber-optic communications system of claim 11 , wherein the light is transmitted from the single-mode fiber to the multi-mode fiber.
14. The fiber-optic communications system of claim 6 , wherein the core has a constant diameter between the first end and the second end.
15. The fiber-optic communications system of claim 6 , wherein the core has non-constant diameter between the first end and the second end.
16. The fiber-optic communications system of claim 6 , wherein the first single-mode fiber and the first adiabatic coupler are housed in a first module, the multi-mode fiber is housed in a second module, and the second single-mode fiber and the second adiabatic coupler are housed in a third module.
17. A fiber-optic communications system, comprising:
a multi-mode fiber having a first end and a second end;
a first optical device;
a first adiabatic coupler optically coupled to the first end of the multi-mode fiber and to one end of the first optical device;
a second optical device; and
a second adiabatic coupler optically coupled to the second end of the multi-mode fiber and to one end of the second optical device, wherein each adiabatic coupler is configured to enable a fundamental mode of light to propagate adiabatically therethrough, wherein the first optical device and the first adiabatic coupler are housed in a first module, the multi-mode fiber is housed in a second module, and the second optical device and the second adiabatic coupler are housed in a third module.
18. The fiber-optic communications system of claim 17 , wherein the modules are interconnected via a plurality of fiber connectors.