Basic Knowledge About Fiber Optic Attenuator

Fiber optic attenuator is inserted into a fiber optic system to reduce the power of the signal. Fiber attenuators can be used to protect the fiber from damage, and adjust the different fiber optic attenuation levels. There are many types of optical attenuators, including fixed, variable, and adjustable attenuators.

1. What are fiber attenuators and what do they do?

Fiber attenuators are devices that are used for power reduction that is being transmitted through a fiber optic cable. There are two main reasons to use a fiber optic attenuator. One is to protect the output fiber optic cable from being damaged by too much power.

The other is to adjust the signal strength so that it matches the requirements of the receiving device. They can be used separately or installed in the optic fiber box or patch panel.


What are fiber attenuators
What are fiber attenuators

2. What type of attenuator?

There are a variety of different types of fiber attenuators, each with its own set of benefits and drawbacks. Some of the most common version of attenuators types include in-line fiber optic attenuator, patch cord attenuators, or variable optical attenuator.

Female to Female inline type attenuator is the simplest attenuator types. The attenuation element is a filter that reduces the power of the signal. It is installed between the transmitter and the fiber optic cable.

The patch cord attenuator is similar to the inline attenuator, but it can be adjusted to provide a variable attenuation. This makes them ideal for situations where the signal strength needs to be adjusted quickly.

Fixed optical attenuators are installed in between the transmitter and the receiver, and they are used to connect fiber optic cables. They provide a fixed amount of attenuation, and they are used to prevent the optical power levels from being too strong.

Compared to the fixed attenuator, variable attenuators refer to an attenuator that can adjust the level of attenuation. This attenuator has a more complex structure and the price depends on the attenuation range.

An adjustable attenuator type is used in fiber optic systems when there is a lot of signal attenuation. This happens when the input optical power of the fiber optic cable is too strong.

Connector type attenuator is mainly used in fiber optic amplifier, add-drop multiplexing system, etc. It can be divided into a male to female types and female types according to the optic connector types.

Singlemode attenuators are designed for use with single-mode fiber optic systems, often used in the long-haul optic network link.

5db attenuator optical fiber is the attenuation fiber with 5db insertion loss, this is insert into the 5db attenuator.

lc upc attenuator is with lc connector.


3. What to Consider When Choosing a Fiber Optic Attenuator

When you are looking for a fiber attenuator, there are a few things you should consider. The first is the fiber optic connector type. The attenuator should have the same fiber connectors type as the fiber you are using, like APC connectors need APC attenuators.

The next thing to consider is the attenuator value. The attenuator should have an attenuation value that is appropriate for your application.

The third thing is the return loss of the attenuator. The last thing to consider is the operating wavelength. The attenuator should have a wavelength range that is compatible with the fiber you are using.

consider dimension when choosing optic attenuator
consider dimension when choosing optic attenuator

4. Fiber Optic Attenuator Performance

4.1 Attenuation and insertion loss

The attenuation index of the fixed optical attenuator is its insertion loss. In addition to the attenuation, the variable fiber optical attenuator also has a separate insertion loss index requirement. Insertion loss is the amount of light that is lost when the light pass the fiber collimator and the attenuation unit.

The accuracy of the transmittance affects how well the attenuation unit can measure how much light has been lost. The coupling process is important for producing a good fiber collimator. Making sure that the fiber is correctly coupled to the self-focusing lens, and the fiber collimating mirrors are aligned correctly.

optic attenuator loss reason
optic attenuator loss reason

4.2 Attenuation Accuracy of Optical Attenuators

Usually, the attenuation accuracy of a mechanical optical attenuator is 0.1dB of its attenuation. The attenuation of the attenuator type depends on the transmittance of the metal chip coating layer.

The optical attenuator of mechanical structure, reading display mode and mechanical adjustment method affect the attenuation accuracy of the optical attenuator.

4.3 Return Loss

The ratio of the optical power incident into the optical attenuator reflected from the attenuator along the incident optical path. The high quality optical attenuator has a return loss above 40dB. The light source of the return loss is the reflection caused by the mismatch of the refractive. Methods to improve return loss include anti reflection coating, use of inclined lenses, mechanical index matching, etc.

5. Applications of Fiber Optic Attenuator

It is mainly used to attenuate the optical power level of an optic signal in the optic link. Among the passive device, its products are only fixed with optic connectors and couplers.

The optical attenuator has the advantages of being cheap, having stable performance, and being easy to use. There is a large market demand for it. The variable optical attenuator is more flexible, and the market demand for it is growing steadily.


6. Summarize

Fiber optic attenuators play a key role in protecting fiber optic transmission equipment. If the signal power is not properly reduced, it will cause damage to the equipment or signal distortion. Downtime is an obvious possibility if too much damage is done.

In a fiber optic communication system, every device counts, no matter how simple or small it is. These tiny devices, like fiber optic attenuators, fiber cables, and optic adapter, make the whole system possible.