Basic physics of optical communication

Optical glass fiber has many desirable characteristics for communication such as  

By far the most important and simple phenomenon that is made use of in optical wave guides is refraction of light. When a ray of light propagates from one medium to another, it undergoes refraction at the interface such that the ratio of the sine of the incident angle and the sine of the refracted angle equals the inverse ratio of the relative refractive index of the two media. Thus, 

It is easy to see from this expression that for some critical angle and a given refractive index ratio, 6 will equal 90° and sin 62 be unity. For all angles greater than the critical angle, d, the incident light will be totally reflected, and we can write 

2 dB/km) became available and the era of optical communications began. Let us see what this 0.2 dB/km translates into in terms of attenuation of the initial energy. Using the above expression, we can write 

We first describe the characteristic drawability feature of glasses which stems from their viscoelastic nature and then describe the fabrication processes for the glass fiber for insulation and reinforcement of polymers and for optical communication purposes, both of which exploit the ability of glass to be drawn 

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