Patent ID: 8867879

Claim:
A single-mode optical fiber, comprising: a central core surrounded by an optical cladding, said central core having (i) an outer radius r 1 , (ii) a maximum refractive index difference Δn 1 relative to said optical cladding of between about 2.6×10 −3 and 3.5×10 −3 , and (iii) a volume V 11 defined as follows: V 11 =2π|∫ 0 r 1 Δn ( r ) rdr|; an intermediate cladding positioned between said central core and said optical cladding, said intermediate cladding having an outer radius r 2 and a refractive index difference Δn 2 relative to said optical cladding; and a buried trench positioned between said intermediate cladding and said optical cladding, said buried trench having (i) an outer radius r 3 of less than 24 microns, (ii) a refractive index difference Δn 3 relative to said optical cladding of between about −15.0×10 −3 and −4.5×10 −3 , and (iii) a volume V 13 of between about 170%·μm 2 to 830%·μm 2 as defined as follows: V 13 = 2 ⁢ π ⁢  ∫ r 2 r 3 ⁢ ( Δ ⁢ ⁢ n ⁡ ( r ) - ( 1 r 2 - r 1 ⁢ ) ⁢ ∫ r 1 r 2 ⁢ Δ ⁢ ⁢ n ⁡ ( r ) ⁢ ⅆ r ) ⁢ r ⁢ ⅆ r  ; wherein said buried trench's volume V 13 and said central core's volume V 11 , expressed in units of %·μm 2 , satisfy the following inequality: V 13 >2.21×10 4 ·exp(−0.117 ·V 11 )+170; and wherein, at a wavelength of 1550 nanometers, the optical fiber has an effective area of about 150 μm 2 or greater.