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Optical Fiber Attenuator Is Divided Into Fixed And Variable

Jul 18, 2017


Fiber Optic attenuator is a very important fiber optical passive device, is an indispensable device in optical fiber CATV. From the market demand point of view, on the one hand, optical attenuator is towards miniaturization, serialization, low price direction. On the other hand, because the ordinary type of optical attenuator has been quite mature, optical attenuator is moving towards high-performance direction, Fiber Optic Attenuator such as intelligent optical attenuator, high return loss optical attenuator. So far the market has formed a fixed, stepper-adjustable, continuous adjustable and intelligent optical attenuator four series.

The ability of any optical fiber system to transmit data depends on the optical power of the receiver, as shown in the figure below, which shows the ber of the data link under the receiving light power. (The BER is the reciprocal of the signal-to-noise ratio, for example, the higher the BER, the lower the signal signal-to-noise ratio.) High or low power can result in higher Ber.

High power, receiving amplifier saturation, low power, may interfere with the signal noise and other issues. Fiber attenuator is mainly used to adjust the light power to the required standards.

Optical fiber attenuator is used to reduce the power of optical signals to a certain degree of equipment. Most people may think that the greater the power of the optical signal, Fiber Optic Attenuator and we often use the optical amplifier to increase the power of the optical signal, then why use fiber attenuator to reduce the power of the optical signal? This is because the power of optical signals over the assembly causes the optical receiver to load too heavily, resulting in distorted signals, Fiber Optic Attenuator so the use of fiber attenuator is required to reduce power. Another case is that the optical signal power of each channel needs to be roughly the same in a multi wavelength fibre optic system, so the fiber attenuator is used to equalize the power of each channel.

Fiber attenuator is generally used in two situations: one is permanently installed in the optical fiber communication link, used to equalize the power of the optical signal between the optical transmitter and the optical receiver; the other is to test the power of the optical signal, which means that the power of the optical signal is reduced by the light attenuator, and then the power allowance in the optical fiber link is tested.

The working principle of optical fiber attenuator

The attenuation of optical signals can be realized by light absorption, light reflection, light diffusion, light scattering, light deflection, light diffraction and light dispersion, and the optical fiber attenuator generally attenuates the optical signal by absorbing light, Fiber Optic Attenuator and its working principle is similar to the principle of absorbing too much light energy by sunglasses. Optical fiber attenuator generally does not use the principle of light reflection and light scattering to achieve the attenuation of optical signals, Fiber Optic Attenuator because light reflection can cause echo reflection, and light scattering will form air gap.

Types of optical fiber attenuator

Optical fiber Attenuator is a wide range of types, according to the use of classification, fiber attenuator can be divided into fixed and variable type.

Fixed fiber Attenuator

Fixed attenuation power of the optical attenuator (e.g. 1 db, 5 db, DB, etc.), such as a-3 db optical attenuator with attenuation power of 3 db. This type of fiber attenuator is generally used in telecommunication networks, optical fiber testing devices, local area networks (LANs), and cable television (CATV) systems.

Fixed fiber attenuator can be divided into online and connector. The appearance of the online fiber attenuator is similar to that of an ordinary fiber optic jumper, and is also an optical connector with different types at both ends of a cable.

The shape of the connector type fiber attenuator is similar to that of the optical connector, which is different from the connector connector interface and the connector interface of the parent head. This kind of fiber attenuator either uses the air gap to achieve attenuation, Fiber Optic Attenuator or the attenuation effect is achieved by adding metal ions to attenuate the fiber. Connector-type optical attenuator can be connected directly to connectors with corresponding interfaces such as FC, St, SC, and LC. In addition to the function of attenuation optical signal power, the fiber attenuator of the parent-mother interface type is like a normal adapter, and the optical attenuator of the male-female interface type is like a light connector.