Silica optical fiber with a double polymer cladding
View Patent ↗An optical fiber comprises a silica multimode optical core having a refractive index n 1 and at least one polymer optical cladding having a refractive index n 2 , with n 1 >n 2 . It further comprises a heterogeneous polymer intermediate optical cladding situated between the multimode core and the optical cladding and having a refractive index substantially equal to the refractive index n 1 of the multimode core.
1. An optical fiber comprising a silica multimode optical core having a refractive index n 1 and at least one polymer optical cladding having a refractive index n 2 , with n 1 >n 2 , the optical fiber further comprising a heterogeneous polymer intermediate optical cladding situated between said multimode core and said optical cladding and having a refractive index substantially equal to said refractive index n 1 of said multimode core.
2. The optical fiber claimed in claim 1 , wherein said intermediate optical cladding has a thickness less than or equal to 10 μm.
3. The optical fiber claimed in claim 1 , wherein said heterogeneous polymer intermediate optical cladding is made from an intrinsically non-homogeneous polymer having local density variations.
4. The optical fiber claimed in claim 3 , wherein said heterogeneous polymer intermediate optical cladding is made from acrylate polyurethane networks.
5. The optical fiber claimed in claim 1 , wherein said heterogeneous polymer intermediate optical cladding is made from an alloy and/or from a mixture of different polymers.
6. The optical fiber claimed in claim 1 , wherein said heterogeneous polymer intermediate optical cladding is made from interpenetrating or semi-interpenetrating polymer networks.
7. The optical fiber claimed in claim 1 , wherein said heterogeneous polymer intermediate optical cladding is made from a polymer containing transparent organic or inorganic particles.
8. The optical fiber claimed in claim 1 , comprising a silica monomode central core with a refractive index n 0 surrounded by a silica multimode core with a refractive index n 1 , with n 0 >n 1 .
9. The optical fiber claimed in claim 8 , constituting an optical amplifier, said monomode central core being doped with an amplifier material.
10. An optical fiber comprising a silica multimode optical core having a refractive index n 1 and at least one polymer optical cladding having a refractive index n 2 , with n 1 >n 2 , the optical fiber further comprising a heterogeneous intermediate optical cladding situated between said multimode core and said optical cladding and having a refractive index such that intermediate optical cladding does not act as a waveguide from multimode optical core.