Classification of optical fiber attenuation

Fiber attenuators are used in fiber optic communication systems to reduce the signal power level without significantly affecting the quality of the signal. There are different types of fiber attenuators available in the market, and they are classified based on their working principle. In this article, we will discuss the different types of fiber attenuators and their working principles.

Fixed Fiber Attenuator

Fixed fiber attenuators are the simplest type of attenuators, and they have a fixed attenuation value. They are used to reduce the signal power level by a specific amount, and they cannot be adjusted. Fixed fiber attenuators work by absorbing the light energy or scattering the light energy over a larger area, thus reducing the power level.

Fixed fiber attenuators are made up of a length of fiber optic cable with a specific amount of loss built into it. They are available in different attenuation values, typically ranging from 1 dB to 30 dB.

Variable Fiber Attenuator

Variable fiber attenuators, as the name suggests, allow for adjustable attenuation. They are used when the attenuation value needs to be changed frequently or when a wide range of attenuation values is required. Variable fiber attenuators work by adjusting the amount of light energy that is absorbed or scattered, thus changing the power level.

Variable fiber attenuators are typically made up of a variable attenuating element, which can be a mechanical device, such as a rotary knob or a sliding mechanism, or an electro-optical device, such as a voltage-controlled liquid crystal.

In-line Fiber Attenuator

In-line fiber attenuators are used to reduce the signal power level while the signal is traveling through the fiber optic cable. They are placed in-line with the fiber optic cable, and they work by absorbing or scattering the light energy.

In-line fiber attenuators are typically used when the signal power level is too high, and it needs to be reduced before reaching the receiver. They are also used in situations where the signal power level needs to be reduced to match the receiver's sensitivity level.

Bulkhead Fiber Attenuator

Bulkhead fiber attenuators are similar to in-line fiber attenuators, but they are used in situations where the attenuation value needs to be changed frequently or when a wide range of attenuation values is required. They are mounted on a bulkhead adapter, which is used to connect two fiber optic cables.

Bulkhead fiber attenuators work by adjusting the amount of light energy that is absorbed or scattered, thus changing the power level. They are typically made up of a variable attenuating element, which can be a mechanical device, such as a rotary knob or a sliding mechanism, or an electro-optical device, such as a voltage-controlled liquid crystal.

Absorptive Fiber Attenuator

Absorptive fiber attenuators work by absorbing the light energy, and they are used when a precise amount of attenuation is required. They are typically made up of a length of fiber optic cable with a specific amount of loss built into it, and they are designed to absorb the light energy at a specific wavelength.

Absorptive fiber attenuators are commonly used in applications such as optical time-domain reflectometry (OTDR) and wavelength division multiplexing (WDM) systems.

Reflective Fiber Attenuator

Reflective fiber attenuators work by reflecting the light energy back to the source, and they are used when a precise amount of attenuation is required. They are typically made up of a length of fiber optic cable with a specific amount of loss built into it, and they are designed to reflect the light energy at a specific wavelength.

Reflective fiber attenuators are commonly used in applications such as OTDR and fiber optic testing.