Fiber attenuation coefficient is an index used to measure the degree of energy loss of optical signals during fiber optic transmission. It represents the amount of attenuation of optical signal strength per unit length, usually in decibels per kilometer (dB/km).
The definition of fiber attenuation coefficient is based on the energy loss of the optical signal in the fiber. When an optical signal is transmitted in an optical fiber, it is affected by a variety of factors, such as the loss of the fiber material, scattering, bending, insertion loss, and so on. These factors cause the intensity of the optical signal to gradually diminish.
The fiber attenuation coefficient can be calculated by the following formula:
Attenuation coefficient (dB/km) = 10 × log10 (input power / output power) / fiber length
Where the input power is the power of the optical signal when it enters the optical fiber, the output power is the power of the optical signal when it is output from the optical fiber, and the fiber length is the length of the optical fiber where the signal is transmitted.
The smaller the attenuation coefficient is, the lower the transmission loss of the fiber is, and the signal transmission distance can be farther. Normally, the attenuation coefficient of single-mode fiber is below 0.2 dB/km, and the attenuation coefficient of multi-mode fiber is below 2 dB/km.
The attenuation coefficient is one of the important performance indicators in fiber optic transmission. A lower attenuation coefficient means lower signal loss, enabling longer transmission distances and higher signal quality. Therefore, when selecting optical fibers, it is necessary to consider their attenuation coefficient and choose optical fibers with lower attenuation coefficients to meet specific application requirements.
