watch A mode is a path that a light wave can follow as it travels down the core of an optical Fiber. The characteristics of an optical Fiber is determined by the three parameters ;
click 1. Composition of the material; that include the information of refractive indices of the material,
watch 2. The nature of light, it means the wavelength of light which is used.
http://camanual.com/faq 3. The diameter of the core and the length of the optical fiber
http://captainaugust.com/?koooas=https-iqoption-com&ec4=75 The possible number of modes that can be travel through the core are related by the above mentioned three parameters via V-number or Normalized Frequency.
http://ortdestreffens.de/?yabloko=bin%C3%A4re-option-broker-paysafecard&b4d=52 The V-Number is a dimensional quantity, that combines all the 3-parameters , like the core radius ‘a’ the index difference, and the operating wavelength. For a single mode fibers, The V-number is always less than and or equal to 2.405 which corresponds to the cut-off wavelength lambda c that separates the single mode region from multi mode region.