What are Fixed Attenuators & Variable Attenuators?

Fiber Optic Attenuator is a device to reduce the optical fiber power at a certain level by a predetermined factor. The intensity of the signal is described in decibels (dB) over a specific distance the signal travels. Attenuator provides a certain amount of isolation between instruments, thus reducing measurement interaction. This can be done by attenuating the unwanted reflected signal due to imperfect matching.

Fiber optic attenuators are used in applications where the optical signal is too strong and needs to be reduced; it is mainly used for fiber optic system of measurement, signal attenuation for short distance communication system and system test, etc. For example, in a multi-wavelength fiber optic system, you need to equalize the optical channel strength so that all the channels have similar power levels. This means to reduce stronger channels’ powers to match lower power channels.

The basic types of optical attenuators are fixed and variable attenuators. The most commonly used type is female to male plug type fiber optic attenuator, it has the fiber connector at one side and the other side is a female type fiber optic adapter. Female to male mechanical attenuator is assembled with a fixed type connector, so it can only be connected with one patch cord, such as LC Attenuator, SC Attenuator, FC Attenuator, ST Attenuator, etc.

Handheld Attenuator

Fixed Attenuators

Fixed value attenuators have fixed values that are specified in decibels. Just its name implies, fixed value attenuator’s attenuation value cannot be varied. The attenuation is expressed in dB. The operating wavelength for optic attenuators should be specified for the rated attenuation, because optic attenuation of a material varies with wavelength. Their applications consist of telecommunication networks, optic fiber test facility, and Local Area Network (LAN) and CATV systems.

Fixed value attenuators are composed of two big groups: In-line type and connector type. In-line type looks like a plain fiber patch cable; it has a fiber cable terminated with two connectors which you can specify types. The in-line fiber optic attenuator is fit to use with optical patch cables. To use these in-line Fiber Optics Attenuators just select the connector type you need ST, SC, LC, & FC Available, the Polish (PC, UPC or APC angled Polish) & the Decibel dB rating.

Variable Attenuators

Variable attenuators come with variety separate designs. They are normal used for testing and measurement, but they also have a wide usage in Edfas for equalizing the light power among separate channels. One type of changeable attenuator is built on a D-shaped fiber as a type of evanescent field device. If a bulk external material, whose refractive index is greater than the mode effective index, replaces a part of the evanescent field reachable cladding, the mode can come to be leaky and some of the optic power can be radiated. If the index of the external material can be changed with a controllable mean, straight through the effects such as thermo-optic, electro-optic, or acoustic-optic, a gadget with controllable attenuation is achievable. Other types of variable attenuators consist of air gap, clip-on, 3-step and more.

As it comes to getting a fiber optic attenuator you have several options listed above, so before you buy one you must be sure at what level you want to attenuate your signal and then choose what type will work best for you. Taking the time to choose the right one can save you big time.

For newest quotes of fixed attenuators and variable attenuators, please contact a Sopto representative by calling 86-755-36946668, or by sending an email to info@sopto.com. For more info, please browse our website.