In a fiber optic communication system an optical attenuator
is an electronic device commonly used to decrease the level of power of an
optical signal. In fiber optics, attenuation is also called transmission loss.
Concerning the distance traveled by the signal in a
transmission medium, it is the reduction in light signal intensity. To limit
the transmission of a digital signal traveling in large distances, attenuation
is an important element. As optical attenuator travels along
with free space or an optical fiber it reduces this optical signal.
When used in fiber optic communications optical fiber
attenuators may employ several principles. The gap loss principle is one common
principle. Attenuators using this principle are sensitive to the modal
distribution ahead of the attenuator. Thus, they should be utilized near or at
the transmitting end. If not, the attenuators can establish less loss than
intended.
Three basic types of optical attenuators are the fixed
attenuator, step-wise attenuator, and the continuously variable attenuator. You
can buy an optical circulator online.
Light signals are reduced by fixed attenuators by a specific
amount with negligible or no reflection. As signal reflection is not an issue,
fixed attenuators are known for more accurate data transmission.
With fixed attenuators, the important elements associated
are the amount of attenuation, flatness over a specified frequency, range,
average and peak power-handling capability, performance over a specific
temperature, voltage standing wave ratio (VSWR), size, and height.
In an electronic circuit, fixed attenuators are also often
used to enhance interstage matching. The optical isolator is
also much in demand.
In variable optical attenuators (VOA), resistors are
replaced with solid-state devices such as and PIN diodes the metal-semiconductor a field-effect transistor (MESFETs). VOA attenuates beam or light signal that to
in a controlled manner, resulting in the production of an output optical beam
with different attenuated intensity.
To regulate optical power levels VOA is usually used in
fiber optic communication systems so that it can prevent damages in optical
receivers which may be due to irregular or fluctuating power levels. Depending
on the manufacturing technology used the price of commercial VOA varies. Some
of the manufacturers of VOA are Timbercon and Arcoptix.