Patent ID: 8798423

Claim:
A single-mode optical fiber, comprising: a central core surrounded by an outer optical cladding, said central core having a radius (R co ) of between about 3.5 microns and 5.5 microns and a refractive-index difference with said outer optical cladding (Dn co −Dn out ) of between about −1×10 −3 and 3×10 −3 ; a first depressed cladding positioned between said central core and said outer optical cladding, said first depressed cladding having an outer radius (R cl1 ) of between about 9 microns and 15 microns and a refractive-index difference with said outer optical cladding (Dn cl1 −Dn out ) of between about −5.5×10 −3 and −2.5×10 −3 ; and a second depressed cladding positioned between said first depressed cladding and said outer optical cladding, said second depressed cladding having an outer radius (R cl2 ) of between about 38 microns and 42 microns and a refractive-index difference with said first depressed cladding (Dn cl2 −Dn out ) of between about −0.5×10 −3 and 0.5×10 −3 ; wherein said outer optical cladding has an outer radius of between about 61.5 microns and 63.5 microns.