Patent ID: 7853110

Claim:
An optical fiber comprising: (i) a glass core ( 20 ) extending from a centerline and including a central core region ( 22 ) with an alpha value of less than 2 and comprising a maximum relative refractive index percent, Δ CMAX , the central core region ( 22 ) having volume V 22 ; a first annular core region ( 24 ) surrounding the central core region ( 22 ); and a second annular core region ( 26 ) surrounding the first annular core region ( 24 ) and having volume V 26 , wherein the second annular core region ( 26 ) has (a) a higher maximum relative refractive index percent Δ 26MAX than that maximum relative refractive index percent Δ 24MAX of the first annular core region ( 24 ), and (b) volume V 26 <4.5% μm 2 and V 22 +V 26 <6.5% μm 2 ; (ii) a glass cladding ( 30 ) surrounding and in contact with the core, the cladding comprising: a first annular cladding region ( 32 ) extending from a radius R C3 to a radius R 32 , wherein R 32 >13 μm and comprising relative refractive index percent Δ 32 (r) %, a maximum relative refractive index percent, Δ 32 MAX and a minimum relative refractive index percent, Δ 32 MIN ; a second annular cladding region ( 34 ) extending from the radius R 32 to a radius R 34 and comprising relative refractive index percent Δ 34 (r) % and a minimum relative refractive index percent, Δ 34 MIN ; a third annular cladding region ( 36 ) surrounding the second annular region ( 34 ) and extending from the radius R 34 to an outermost glass radius R 36 ; wherein Δ CMAX >Δ 26MAX >Δ 32MAX ; Δ 32MIN >Δ 34MIN , and Δ 34MIN <−0.1; and the core and the cladding provide a fiber with cable cutoff less than 1500 nm, dispersion D at 1550 nm of 3≦D≦8 ps/nm/km, and an effective area at 1550 nm greater than 80 μm 2 , and bend losses less than 5 dB/m at 1550 nm when the fiber is wrapped around 15 mm radius mandrel.