Single Mode Step Index Optical Fiber

The fiber has lower bandwidth.

Single mode step index optical fiber. Step index means sharp step in the index of refraction between core and cladding interface. Therefore this type of step index fiber is known as single mode step index fiber. Single mode step index optical fiber structure and plot it is also a step index fibre but due to its small diameter of the core 2 10 micrometre it can support only single mode of light. The bandwidth is about 50 mhz km for multimode step index fiber whereas it is more than 100 mhz km in case of single mode step index fiber.

This is the case in. The step index profile is used in most single mode fibers and some multimode fibers. Examples of standard core and cladding diameters 2a 2b are 8 125 50 125 62 5 125 85 125 or 100 140 units of µm. Modes are the possible solutions of the helmholtz equation for waves which is obtained by combining maxwell s equations and the boundary conditions.

Multimode graded index fiber. Single mode step index fiber. This indicates that in step index core and cladding have their own constant index of refractions n1 and n2 respectively. Waves can have the same mode but have different frequencies.

Rayleigh scattering microscopic scale variations in the index of refraction of the core material can cause considerable scatter in the beam leading to substantial losses of optical power. The step index cable cross section is depicted in the figure 2. How the wave is distributed in space. There are several causes of attenuation in an optical fiber.

In single mode light takes single path through the fiber core. Typical values range from 10 db km for step index fibers at 850 nm to a few tenths of a db km for single mode fibers at 1550 nm. The diameter of the core is between 50 200µm in the case of multimode fiber and 10µm in the case of single mode fiber. In single mode step index fiber there is no distortion.