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Introduction to Optical Device Attenuation

Today I will introduce to you that the fiber attenuator is an optical device that can reduce the energy of the optical signal. By attenuating the input optical power, it can avoid distortion of the optical receiver due to excessive input optical power. Optical fiber attenuator, as an optical passive device, is usually made of attenuating optical fiber doped with metal ions, which can adjust the optical power to the required level. It is mainly used for debugging optical power performance and debugging optical fiber instruments in optical communication systems. Calibration correction and fiber optic signal attenuation.

Why Use Fiber Optic Attenuators

The intensity of optical signals received by various optical receiving devices is limited, and it needs to be within a certain range. Devices with too weak or too strong optical power cannot work normally. When the optical power is too strong, the optical attenuation will be used to adjust the optical power to reduce it to an appropriate range. Otherwise, even if the device can be used, it will affect the service life.

The attenuation power of a fixed fiber attenuator is fixed (such as 1dB, 5dB, 10dB, etc.), and the attenuation power of a -3dB fiber attenuator is 3dB. This fiber optic attenuator is typically used in telecommunication networks, fiber optic test equipment, local area network (LAN) and cable television (CATV) systems. Fixed fiber attenuators can be divided into online and connector types.

The shape of the connector-type optical fiber attenuator is similar to that of an optical connector. The difference is that the two ends of the connector-type fiber optic attenuator are the male connector interface and the female connector interface. This fiber optic attenuator either uses an air gap to achieve attenuation, or attenuates the fiber by doping metal ions to achieve the attenuation effect.

The attenuation power of the adjustable optical fiber attenuator is not constant, but changes with the change of conditions, and its change span is 0.5dB, 20dB, 50dB, etc., and some even reach the accuracy of 0.1dB and 0.01dB. Tunable fiber optic attenuators are generally used for precise testing and measurement of optical fibers, and are also widely used in the occasion of erbium-doped fiber amplifiers. Its function is to balance the optical signal power in different channels.

Optical fiber attenuators are divided into the following four categories according to different interfaces

SC fiber optic attenuator: applied to SC fiber optic interface, similar to RJ-45 interface, but the SC interface is flatter, and the contact piece inside is a copper column;

LC optical fiber attenuator: applied to LC optical fiber interface, can be used to connect SFP module, adopts modular jack (RJ) latch mechanism, easy to operate, often used in routers;

FC optical fiber attenuator: applied to FC optical fiber interface, the jacket is wrapped with a metal sleeve, and the fastening method is a turnbuckle. Generally used on the ODF side, mostly used for patch panels;

ST fiber optic attenuator: applied to ST fiber optic interface, the shell is round and fastened with a screw buckle, often used in fiber optic distribution frames.