Few mode optical fibers for mode division multiplexing
An optical fiber comprising: (i) a core having a refractive index profile; (ii) an annular cladding surrounding the core; (iii) a primary coating contacting and surrounding the cladding, the primary coating having an in situ modulus of less than 0.35 MPa and an in situ glass transition temperature of less than −35° C.; and (iv) a secondary coating surrounding the primary coating, the secondary coating having an in situ modulus of greater than 1200 MPa; wherein the refractive index profile of said core is constructed to provide an LP11 theoretical cutoff wavelength greater than 2.0 μm and an effective area greater than 110 microns 2 at 1550 nm.
1. An optical fiber comprising:
a core having a refractive index profile;
an annular cladding surrounding the core;
a primary coating contacting and surrounding the cladding, the primary coating having an in situ modulus of less than 0.35 MPa and an in situ glass transition temperature of less than −35° C.;
a secondary coating surrounding the primary coating, the secondary coating having an in situ modulus of greater than 1200 MPa;
wherein the refractive index profile of said core is constructed to provide a theoretical cutoff wavelength of an LP11 mode greater than about 2.0 μm and an LP01 effective area greater than 110 μm 2 at 1550 nm.
2. The optical fiber according to claim 1 , wherein said fiber comprises a step refractive index profile, wherein said core is a glass core, and said cladding is a glass cladding;
said core comprises:
a radius r c from about 6 μm to about 15 μm;
a maximum relative refractive index Δ 1MAX from about 0.2% to about 0.55% relative to the glass cladding;
an LP01 effective area greater than about 110 μm 2 and less than about 210 μm 2 , a theoretical cutoff wavelength of the LP02 mode is less than about 1800 nm; and
said glass cladding comprises a maximum relative refractive index Δ 4MAX such that Δ 1MAX >Δ 4MAX .
3. The optical fiber according to claim 2 , wherein the MPI is less than −30 dB at a wavelength of 1550 nm.
4. The optical fiber according to claim 3 , wherein the MPI is less than −35 dB at a wavelength of 1550 nm.
5. The optical fiber according to claim 2 , wherein the differential delay between the LP01 and LP11 modes is less than about 0.5 ns/km at a wavelength of 1550 nm.
6. The optical fiber according to claim 2 , wherein a theoretical cutoff of an LP11 mode is greater than 2.15 μm and the MPI is less than −30 dB at a wavelength of 1550 nm.
7. The optical fiber of claim 2 , wherein said optical fiber has an LP01 attenuation of <0.22 dB/km.
8. The optical fiber of claim 2 , wherein said optical fiber has an LP11 attenuation of <0.25 dB/km.
9. A mode division multiplexing (MDM) optical transmission system, comprising:
a transmitter configured to transmit first and second guided-wave optical signals respectively having a first and a second wavelength in an LP11 and an LP01 mode, respectively;
a receiver configured to receive and wavelength demultiplex the first and second optical signals; and
the few mode optical fiber of claim 2 configured to optically connect the transmitter and the receiver and support the transmission of the first and second guided-wave optical signals.
10. The optical fiber according to claim 1 , wherein said fiber has graded index glass core and said cladding is a glass cladding.
11. The optical fiber according to claim 10 , wherein;
said core comprises:
a radius r c from about 6 μm to about 15 μm;
a maximum relative refractive index Δ 1MAX from about 0.2% to about 0.55% relative to the glass cladding;
an LP01 effective area greater than about 110 μm 2 and less than about 210 μm 2 , a theoretical cutoff wavelength of the LP02 mode is less than about 1800 nm; and
said glass cladding comprises a maximum relative refractive index Δ 4MAX such that Δ 1MAX >Δ 4MAX .
12. The optical fiber of claim 11 , wherein the MPI is less than −30 dB at a wavelength of 1550 nm.
13. The optical fiber of claim 11 , wherein the MPI is less than −35 dB at a wavelength of 1550 nm.
14. The optical fiber according to claim 11 , wherein the differential delay between the LP01 and LP11 modes is less than about 0.5 ns/km at a wavelength of 1550 nm.
15. The optical fiber according to claim 11 , wherein a theoretical cutoff of an LP11 mode is greater than 2.15 μm and the MPI is less than −30 dB at a wavelength of 1550 nm.
16. The optical fiber of claim 11 , wherein said optical fiber has an LP01 attenuation of <0.22 dB/km.
17. The optical fiber of claim 11 , wherein said optical fiber has an LP11 attenuation of <0.25 dB/km.
18. The optical fiber according to claim 11 , wherein said fiber core has an alpha value greater than 2.3 and less than about 2.7 at a wavelength of 1550 nm.
19. A mode division multiplexing (MDM) optical transmission system, comprising:
a transmitter configured to transmit first and second guided-wave optical signals respectively having a first and a second wavelength in an LP11 and an LP01 mode, respectively;
a receiver configured to receive and wavelength demultiplex the first and second optical signals; and
the few mode optical fiber of claim 11 configured to optically connect the transmitter and the receiver and support the transmission of the first and second guided-wave optical signals.