What is a variable optical attenuator?
What is a variable optical attenuator?
A variable optical attenuator is used to trim a fiber’s optical signal power levels. Applications include leveling the power exiting an optical amplifier across a fiber’s spectrum, and protecting a photodetector at a receiver from being overwhelmed by too strong a signal (Fig. 4.3).
How does a variable optical attenuator work?
Optical attenuators usually work by absorbing the light, like sunglasses absorb extra light energy. Another type of attenuator utilizes a length of high-loss optical fiber, that operates upon its input optical signal power level in such a way that its output signal power level is less than the input level.
What is fiber attenuation?
The attenuation of an optical fiber measures the amount of light lost between input and output. Total attenuation is the sum of all losses. Optical losses of a fiber are usually expressed in decibels per kilometer (dB/km).
What are fiber optic attenuators used for?
Attenuators are used to temporarily add a calibrated amount of signal loss in order to test the power level margins in a fiber optic communication system. In the second case, attenuators are permanently installed in a fiber optic communication link to properly match transmitter and receiver optical signal levels.
Why does attenuation occur in optical fiber?
The attenuation of the optical fiber is a result of two factors, absorption and scattering. The absorption is caused by the absorption of the light and conversion to heat by molecules in the glass. The largest cause of attenuation is scattering.
What is attenuation in optical fiber communication?
Attenuation in fiber optics, also known as transmission loss, is the reduction in intensity of the light beam (or signal) with respect to distance travelled through a transmission medium.
What is the attenuation in optical fiber?
In optical fibers, attenuation is the rate at which the signal light decreases in intensity. For this reason, glass fiber (which has a low attenuation) is used for long-distance fiber optic cables; plastic fiber has a higher attenuation and, hence, shorter range.
What are the types of attenuation in optical fiber?
Attenuation on Optical Fiber (1) Intrinsic loss in the fiber material. (2) Scattering due to micro irregularities inside the fiber. (3) Micro-bending losses due to micro-deformation of the fiber. (4) Bending or radiation losses on the fiber.
What are the main causes of attenuation in optical fiber?
The attenuation of the optical fiber is a result of two factors, absorption and scattering. The absorption is caused by the absorption of the light and conversion to heat by molecules in the glass. Primary absorbers are residual OH+ and dopants used to modify the refractive index of the glass.
What is the main cause of attenuation?
Attenuation is the reduction in power of the light signal as it is transmitted. Attenuation is caused by passive media components, such as cables, cable splices, and connectors. Dispersion is the spreading of the signal over time.
What are the kinds of attenuation in fiber optics?
