Patent ID: 7899293

Claim:
A single-mode optical fiber, comprising: a central core having an index difference Dn 1 with an outer optical cladding; a first intermediate cladding having an index difference Dn 2 with the outer optical cladding; a first depressed cladding having an index difference Dn 3 with the outer optical cladding that is less than or equal to about −5×10 −3 ; a second intermediate cladding having an index difference Dn 4 with the outer optical cladding; and a second depressed cladding having a negative index difference Dn 5 with the outer optical cladding; wherein, in absolute value, the index difference Dn 5 of the second depressed cladding with the outer optical cladding does not exceed the index difference Dn 3 of the first depressed cladding with the outer optical cladding; wherein, at a wavelength of 1310 nanometers, the optical fiber has a mode field diameter (MFD) of 8.0 μm to 10.1 μm; wherein, at a wavelength of 1625 nanometers, the optical fiber has bending losses less than or equal to about 0.1 dB/10 turns for a bending radius of 15 millimeters; and wherein, at a wavelength of 1625 nanometers, the optical fiber has bending losses less than or equal to about 0.5 dB/turn for a bending radius of 7.5 millimeters.