What Are the Common Fiber Optic Attenuators?

Fiber optic attenuator is an optical device that can reduce the energy of optical signal. Through the attenuation of input optical power, it can avoid the distortion of optical receiver due to too strong input optical power.

As an optical passive device, fiber attenuator is usually made of attenuation fiber with metal ions. It can adjust the optical power to the required level. It is mainly used in optical communication system to debug the optical power performance, calibrate the calibration of optical fiber instrument and reduce the attenuation of optical fiber signal.

1. Why use fiber optic attenuators?

The intensity of optical signal received by various optical receiving equipment is limited, and the equipment can not work normally if the optical power is too weak or too strong within a certain range. When the optical power is too strong, the optical power will be adjusted by light attenuation to reduce it to an appropriate range, otherwise even if the equipment can be used, it will affect the service life.

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

The shape of plug-in fiber optic attenuator is similar to that of optical connector. The difference is that both ends of plug-in fiber optic attenuator are male connector interface and female connector interface respectively. This fiber optic attenuator either uses air gap to achieve attenuation, or uses metal ions to attenuate optical fiber to achieve attenuation effect.

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

2. Fiber optic attenuators are divided into the following four categories according to different interfaces

SC fiber optic attenuator: it is applied to SC optical fiber interface, which is similar to RJ-45 interface, but the SC interface is more flat and the contact inside is a copper column.

LC fiber optic attenuator: it is applied to LC optical fiber interface and can be used to connect SFP module. Modular jack (RJ) latch mechanism is adopted, which is easy to operate and commonly used in routers.

FC fiber optic attenuator: it is applied to FC optical fiber interface. The outer sleeve is wrapped with metal sleeve, and the fastening method is turnbuckle. It is generally used on the ODF side and is mostly used for distribution frames.

ST fiber optic attenuator: it is applied to st optical fiber interface. The shell is circular and fastened with turnbuckle. It is commonly used in optical fiber distribution frame.