How optical attenuation can be determined? - Technopediasite


Wednesday, March 4, 2020

How optical attenuation can be determined?

How optical attenuation can be determined : First of all, let me tell you that is famous for providing all kinds of technical support in the telecom sector. If you need any kind of technical support related to the telecom sector, then just tell your requirement in detail in the comment box. All of you will be treated as our friend and help for free. Now I would like to draw your attention towards " Attenuation of Optical Fiber " topic. You all must have heard about the attenuation many times, but it is probably not known how to get determine.How to determine the attenuation in optical fiber today I am discussing in this article.

If we talk about attenuation, we can only say that " attenuation is the loss of optical power as light travel down a fiber ". We can also say that attenuation is the reduction of signal strength or light power over the length of the fiber and it is measured in dB/km. Typical value are 0.35dB at 1310nm and 0.25dB at 1550.
How optical attenuation can be determine in details
Optical Attenuation

Attenuation in Optical Fiber

In optical fiber attenuation is mainly determined by three types of loss: absorption loss, scatter loss and twist loss. Scatter loss is also known as dispersion loss in which broadening of an optical signal that result form the many wavelength components travelling at different rates.

Bend in the optical fibers will cause radiation loss. Indeed, in two cases a bend is produced in the optical fiber. One is that the curvature radius of the bend is much larger than the diameter of the fiber (such a bend can occur when fiber cable is laid).

The second case is microbend. There are many reasons for microbands. Microbends, limited to process conditions, can occur during the process of producing fiber and cable. Microbands of different curvature radii are randomly distributed along the fiber.

The twist loss/bend loss mode is related to the field diameter. The bend loss of the G.652 fiber should not be larger than 1dB in the 1550nm wavelength region, and the bend loss of the G.655 fiber should not be greater than 0.5dB in the 1550nm region.

The loss of absorption is due to the fiber content material where excessive metal impurities and OH-ions absorb light causing damage.

In the optical fibers the scattering loss often occurs in the case that some portion of optical power is scattered outside the fiber when uneven refractive index distribution emerges within the local field fiber and due to subtle changes in fiber material density and uneven light. Causes scattering. Density of compositions like SiO2, GeO2 and P2O5.

If some defect occurs or some bubbles and gas scabs remain at the core-cladding boundary. The physical amplitude of these structural defects is much larger than that of lightwave, due to which the wavelength scattered independently and shifts the entire curve of the upward fiber loss spectrum. However, such scattering loss is much lower than the former.

Now finally we can say that attenuation constant of single mode fiber at 1310nm and 1550nm  is 0.3~0.4dB/km (1310nm) and 0.17~0.25dB/km (1550nm), respectively. In optical fiber type G.652, the attenuation constant at 1310nm and 1550nm should be less than 0.5dB/km and 0.4dB/km, respectively.

You can also READ : How many types of single mode fiber
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1 comment:

  1. The article contains too much essential information I have to spread among my colleagues. Thanks a lot for your submission.