Optical Fiber Calculations

Enter in these first 4 parameters which describe the properties of the optical fiber. Then enter the maximum amount of light you are able to enter into the fiber. From these parameters this calculator will tell you numerous capabilities and characteristics of your fiber. In addition, the graph below shows a Gaussian estimation of where the majority of your field lies within your fiber (in the core/cladding).

Wavelength (λ):	[um] (1.3-1.6)
Core radius (a):	[um]
Index of Core* (n1):
Index of Cladding* (n2):
Maximum intensity of light (Io):	[uW]
(*NOTE: n1 must be slightly larger than n2 to guide light.)
Numerical Aperature (NA):
V-Number (V):
Mode Type:	[Single mode: V < 2.405]
Number of Modes:	[Single mode: V < 2.405]
Spot size radius (wo):	[um]
Mode Field Diameter (MFD):	[um]
Power at MFD:	[W]

Light Profile in Optical Fiber
with above Parameters

The location where these two graphs intersect show the boundary of the Mode Field Diameter.

Equations used above:

Numerical Aperature	NA = √(n12-n22)
V-number	V = 2*π*a*NA/λ
Spot size:	wo = a*(.65 +1.619*V-1.5+2.879*V-6)
Mode Field Diameter:	MFD = 2*wo
Intensity at MFD:	I(wo) = Io*e-2 = .135*Io