Fiber optic attenuators come in various kinds. There are a variety of kinds of optical attenuators in the market. We can classify them in different views, including the connector type, the type of cable and so on. In general, we divide them in two categories: fixed optical attenuators (FOA) and optical variable attenuators (VOA). In the context of the various kinds of the cables they have different mode like- into multi-mode and single mode attenuators.
Fixed Optic Attenuator
Fixed attenuator as the name suggests clearly, provides an unchanging amount of attenuation within optical fiber. We can express that in decibels generally between 1dB and 30dB. This should be 1dB, 5dBor 10dB, etc. Fixed optic attenuators could employ a variety of theories to perform their functions. The most popular optical attenuators typically use either doped fibers or misaligned splices or total power. Non-preferred attenuators usually utilize the principle of gap loss and reflection.
As illustrated in the image below, fixed-value attenuators comprise of connector type and in-line type. In-line type appears like a simple fibre patch cable. The optical attenuators in-line are built in patch cables. Connector type attenuators resemble the bulkhead fiber connector. Most often, it comes with an male plug connector on one end to permit the fiber attenuators to connect directly into adapters or receivers in the patch panel, It has a female fiber optic adapter which allows that the patches cords be connected into. There are female to optical attenuators that are able to use as adapters or attenuators simultaneously. Their uses include optical fiber test facilities, Local Area Network (LAN) and CATV systems.
Optic Variable Attenuator
Optic variable attenuator, also known as the variable optical attenuator (VOA) typically employs the neutral density filter variable. VOA utlizes for testing and measurement. However, it can also commonly use in Erbium Doped fiber amplifiers (EDFA) to equalize the power of light across various channels. It is stable, wavelength sensitive as well as mode-insensitive and providing a wide dynamic range.
In essence, there are two kinds of optical variable attenuators that are stepwise variable attenuators. Attenuators that are stepwise can alter the level of attenuation in well-known steps, such as 0.1dB, 0.5dB or 1dB. Attenuators that are continuously variable give a precise level of attenuation via a flexible adjustment. This means that operators can to adjust the attenuator’s settings to adjust to the demands of changing rapidly and precisely, without disruption to the system.
Monomode and Multimode Fiber Optic Attenuator
Because fiber optic attenuators can utilize with two types of fiber cables: multimode and single mode optical attenuators is classficable as single mode or multimode. Attenuators made of fiber optics are generally employed in single mode long-haul projects. This is why the most popular type is also a single-mode type. But, while fiber optic attenuators typically emplys in only one mode of operation, there’s multi-mode attenuators for fiber optics that usable to be paired to multimode fiber cable. When selecting one kind that has optical attenuators over another it is essential to think about the attenuation range, as well as the wavelength.
4. When should you use the Fiber Optic Attenuators?
When you are considering whether to utilize fiber optic attenuators within your device, you will find typically two scenarios in which you’ll require attenuators for fiber optics.
- One example is the case when fiber optic attenuators emplysto decrease the receiver’s power. Sometimes, the signals reaching the receiver becomes too powerful and can overwhelm the receiver elements. The power of the receiver influence by two elements which tranmits into the fiber, and the amount of power lost to the attenuator. Too much receiver powercan cause by the mismatch between the transmitters/receivers. It can cause the use of media converters designed for a much longer distance. In this situation optical attenuators paced in the link fiber to decrease the power of the signal and ensure that the signal strength is in line with.
- Another example is when attenuators emplys to test the margins of power levels. When the transmitter turns on and using a fiber-optic power meter. Also, it sets to the system’s working wavelength, an attenuator could be used to measure the system’s power.
5. How do I Use Fiber Optic Attenuators for Data Link?
In single-mode systems, specifically analog CATV system. The most crucial factor that determines the correct loss is the reflectance or return loss. Numerous types that use optical attenuators (especially ones with gap loss) plagies by the issue of high reflectance. As a result, they could negatively affect transmitters, just as connectors with high reflectance. Read more.