TIA's Glossary of Telecommunication Terms
0-9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
normalized frequency ( V )
1. In an optical fiber, a dimensionless quantity, V , given by 
where a is the core radius, 
is the wavelength in vacuum, n 1 is the maximum refractive index of the core, and n 2 is the refractive index of the homogeneous cladding. Note 1: In multimode operation of an optical fiber having a power-law refractive index profile, the approximate number of bound modes, i.e., the mode volume, is given by 
where V is the normalized frequency greater than 5 and g is the profile parameter. Note 2: For a step index fiber, the mode volume is given by V 2/2. For single-mode operation, V < 2.405. Synonym V number. 2. The ratio between an actual frequency and a reference value. 3. The ratio between an actual frequency and its nominal value. (188)