Views:0 Author:Site Editor Publish Time: 2021-08-03 Origin:Site
The quartz fiber doped with rare earth elements can form a multi-level laser system. The input signal light is directly amplified by the pump light, and the fiber laser is formed by providing appropriate feedback. The development and application of Nd doped fiber amplifiers are limited due to the deviation from the best sink port of optical fiber communication and other reasons. EDFA and PDFA work in the lowest loss (1550nm) and zero dispersion (1300nm) window of optical fiber communication, respectively. TDFA works in the S-band, which is very suitable for the application of optical fiber communication system. EDFA, in particular, has developed most rapidly and has been put into practice.
Here is the content list:
What is the basic structure of an EDFA optical amplifier?
How is EDFA optical amplifier classified?
What are the Specifications of the EDFA Optical Amplifier?
EDFA optical amplifier is mainly composed of erbium-doped fiber (EDF), pump light source, optical coupler, optical isolator and optical filter. The signal light and pump light can propagate in the same direction (same direction pumping), opposite direction (reverse pumping) or two directions (bidirectional pumping) in erbium-doped fiber. When the signal light and the pump light are injected into the erbium fiber at the same time, the erbium ions are excited to the high energy level under the action of the pump light, and decay to the metastable energy level quickly. When they return to the ground state under the action of the incident signal light, they emit photons corresponding to the signal light, so that the signal is amplified.
EDFA optical amplifiers can be divided into three types according to different pumping modes.
The first one is forward pumping, which means that the pump source and the output signal are injected into the erbium-doped fiber from the same direction. The EDFA with this pumping mode has good noise performance.
The second type is backward pumped, which means that the pump source and the input signal are injected into the erbium-doped fiber from two opposite directions. Its advantage is that the output signal power is high.
The third type is the bidirectional pump type. It is easy to know that it has both the same direction pump and the reverse pump. The output signal power of EDFA pumped by this way is 3 dB higher than that of a single pump source, and the amplification characteristics are independent of the signal transmission direction.
The specifications of the EDFA optical amplifier are the important factors for its comparative evaluation.
1. Power gain G(Db)
Power gain is defined as the ratio of output signal power to input signal power. It shows the amplification ability of the optical amplifier. The gain is related to many factors such as pump power and fiber length.
The power gain of the optical amplifier increases with the increase of the pump power, but when the pump power reaches a certain value, the gain of the amplifier saturates, that is, the pump power increases again, but the gain basically remains unchanged. The same is true for the length of erbium-doped fiber, but when the fiber length reaches a certain value, the gain decreases gradually. Therefore, in the case of a given erbium-doped fiber, we should choose the appropriate pump power and fiber length to achieve the maximum gain. At present, the main pump wavelengths are 0.98 μm and 1.48 μm.
2. Output saturation power (mW or dBm)
Output saturation power is a parameter describing the relationship between input power signal and output signal power. In EDFA optical amplifiers, the input signal power is not directly proportional to the output signal power, but tends to be saturated. The maximum output power of EDFA is usually expressed by dB saturated output power, which represents the maximum output capacity of EDFA optical amplifier.
3. Noise figure NF(dB)
Noise figure is the ratio of input signal-to-noise ratio and output signal-to-noise ratio, which is used to measure the noise characteristics of EDFA. The main sources of EDFA noise are shot noise of signal light, beat noise between a signal light wave and amplifier spontaneous emission light wave, shot noise of amplified spontaneous emission light and beat noise between different frequency light waves of optical amplifier spontaneous emission.
4. Gain bandwidth (nm)
5. Gain flatness
6. Gain coefficient
Erbium doped fiber amplifier (EDFA) is an important device widely used in an optical fiber communication system. In optical fiber communication system, erbium-doped fiber amplifier (EDFA) is generally used for the preamplifier, the power amplifier and the line amplifier. Hengchi Electronic Equipment Co., Ltd. has more than 14 years of experience in the design of complex optical fiber and electronic circuits. All its products can stably serve in optical fiber communication projects and obtain a high evaluation. If you are engaged in EDFA optical amplifier related industries or have purchase demand, you can consider our cost-effective products.