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What is the Characteristic of EDFA Optical Amplifiers?
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What is the Characteristic of EDFA Optical Amplifiers?

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What is the Characteristic of EDFA Optical Amplifiers?

Compared with the traditional amplification method, the fiber amplifier does not need simultaneous interpreting processes, such as photoelectric conversion, electro-optical conversion and signal regeneration, and can directly amplify optical signals. EDFA optical amplifier has many excellent characteristics, and also has many advantages in the system application, which makes WDM technology become a reality, so it has been widely concerned. Therefore, EDFA optical amplifier, which uses erbium-doped single-mode fiber as gain medium, produces particle number inversion under the action of pump light and realizes stimulated radiation amplification under the guidance of signal light, has become an ideal amplifier in modern optical fiber communication system.


Here is the content list:

How does EDFA optical amplifier work?

What are the characteristics of EDFA optical amplifiers?

What are the applications of EDFA optical amplifiers?


How does EDFA optical amplifier work?

EDFA optical amplifier uses trivalent rare earth Erbium element as its core structure in the quartz fiber core. Under the excitation of pump light, the particles in this kind of fiber undergo two processes: absorption pump light transition and non-radiation transition, forming the inverse distribution of the number of particles. Under the action of the signal light, the stimulated radiation is generated, and finally the same photons as the signal photons are emitted, forming the amplification of the light. This is how the EDFA optical amplifier works.


What are the characteristics of EDFA optical amplifiers?

The main characteristics of the EDFA amplifier include gain characteristics, output power characteristics and noise characteristics.

1. Gain characteristics

Gain characteristic refers to the ratio of output power to input power of erbium-doped fiber amplifier, which represents the optical amplification capacity of erbium-doped fiber amplifier, generally between 15-40dB. The gain size is affected by factors such as optical fiber concentration, pump power, optical fiber length, and pump wavelength. Doping excessive bait ions will instead cause the concentration reversal to decrease, resulting in saturation increase. When the pump power is small, the output optical power increases rapidly, the pump power increases continuously and the gain of the optical amplifier becomes saturated. Even if the pump power is increased significantly, the gain will remain essentially unchanged. When the pump power is insufficient, the fiber amplifier will not gain but decay.

2. Output power characteristics

The maximum output power of EDFA is usually expressed as 3 dB saturation output power, which means the corresponding output power when the saturation gain decreases by 3 dB. This parameter represents the maximum output capability of EDFA. In order to improve the output power of EDFA, some companies use a two-stage pumping mode, which can not only improve the noise figure, but also increase the output power. However, for the sake of laser safety and fiber nonlinearity, the output power is generally limited below + 17 dBm, which is also the safety requirement of laser 3A.

3. Noise characteristics

Noise figure NF (noise figure) can be used to measure the noise characteristics of EDFA, which is defined as the ratio of the total output optical power with signal to the output optical power without signal. The typical value is 515db and the minimum is 3dB. There are four kinds of noise in EDFA: shot noise of the signal light, shot noise of amplified spontaneous emission (ASE), beat noise between ASE spectrum and beat noise between ASE spectrum and signal light. Among the four kinds of noise, the latter two have the greatest influence, especially the third one


What are the applications of EDFA optical amplifiers?

EDFA can be used in large capacity and high -speed optical communication system to make up for the defects of the low sensitivity of high-speed system receiver and short transmission distance without a relay. It can also be used in a long-distance optical communication system, which can increase the relay distance, reduce the number of regenerative repeaters, and greatly reduce the construction cost. It can also be used to compensate for the optical loss caused by power distribution in the optical fiber user access network system and play the role of the relay. In addition, adding EDFA to the WDM system can solve the problem of insertion loss and reduce the influence of dispersion. EDFA used in optical fiber CATV system can compensate the insertion loss of optical power distributor before distribution, and greatly improve the scale of distribution network and the number of users. In the all-optical communication system, the combination of wavelength division multiplexing and fiber amplifier can realize the all-optical communication network without upper and lower optical path, and expand the network scale.


EDFA optical amplifier is one of the key technologies in the WDM optical communication network. With the development of society, EDFA optical amplifier is the main choice of optical fiber amplifier at present and in the future, which plays a key role in optical fiber communication system. All the products produced by Hengchi Electronic Equipment Co., Ltd. can stably serve optical fiber communication engineering and obtain a high evaluation. If you are engaged in EDFA optical amplifier industry or have purchase demand, you can consider our high-quality products.

Our engineers has over 14 years experience designing complex fiber optic and electronic circuits.




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