Patent ID: 8750664

Claim:
A bend insensitive single mode comprising: a bare glass fiber ( 11 ) with a round cross section and two resin protective layers ( 12 , 13 ) with circular cross sections surrounding the outer of the bare glass fiber ( 11 ); wherein the bare glass fiber ( 11 ) is composed by a core layer ( 111 ) with a round cross section and two claddings ( 112 , 113 ) with circular cross sections, a refractive index of the core layer ( 111 ) is higher than refractive indexes of the two claddings ( 112 , 113 ); a refractive index difference (Δ 1 ) between the core layer ( 111 ) and the first cladding ( 112 ) Δ 1 is between 0.0033˜0.0072, a refractive index difference (Δ 2 ) between the first cladding ( 112 ) and second ( 113 ) claddings Δ 2 is between −0.0016˜0, a thickness (a) of the core layer ( 111 ) is between 2.7˜4.1 μm, a thickness (b) of the first cladding ( 112 ) is between 0.5˜2.3 μm and a thickness (c) of the second cladding ( 113 ) is between 56.7˜59.8 μm; and the second cladding ( 113 ) is made of pure SiO 2 , a refractive index profile of the core layer ( 111 ) follows a power function distribution, and the refractive index profiles of the two claddings ( 112 and 113 ) follow a ladder-type distribution.