Basic knowledge of optical fiber communication principle,

Basic knowledge of optical fiber communication principle - 2016 04 - And the law of reflection and refraction of light in the process of transmission, in two different transmission medium interface will produce the following behavior: a part of the incident light will be reflected part of incident light will go into the second medium, and the product refractive index n = light travels in a vacuum/light propagation velocity in the medium. Total reflection: when n1 & gt; N2, along with the increase of incident Angle, the Angle of incidence reaches a certain value, the Angle of refraction at 90 ℃, we at this time of the incident Angle is called the critical Angle & alpha; 0. When the incident Angle is greater than the critical Angle, total reflection will occur. According to the law of refraction, we can find out the critical Angle, at this time & alpha; 2=90° The n1 & middot; sinα 0 = n2· sin90° So sinα 0 = n2 / n1 light principle of fiber optical communication is the use of the principle of total reflection, when light injection Angle to satisfy certain conditions, the light can be in the optical fiber ( Optical waveguide) In total reflection, so as to achieve the purpose of the long distance transport. Condition: n1 & gt; n2> N0n0: the index of refraction of air n1: the refractive index of fiber core n2, the refractive index of cladding & alpha; > α 0α 0: incidence Angle, and sinα 0 = n2 / n1 the structure of the fiber optical fiber communication advantages: large capacity long distance relay adaptable small volume, light weight, easy installation and maintenance of the selection is rich, low price confidentiality is strong