L-band EDFA amplifier system technical scheme

1. Erbium-doped fiber
Erbium is a rare earth element with an atomic number of 68 and an atomic weight of 167.3. The erbium ion's electronic energy level is shown in the figure, and the transition from the lower energy level to the upper energy level corresponds to the absorption process of light. The change from the upper energy level to the lower energy level corresponds to the light emission process.

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2. EDFA principle

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EDFA uses erbium ion-doped fiber as the gain medium, which produces population inversion under pump light. It realizes stimulated radiation amplification under the induction of signal light.
Erbium ions have three energy levels. They are at the lowest energy level, E1, when they are not excited by any light. When the fiber is continuously excited by the pump light source laser, the particles in the ground state gain energy and transition to a higher energy level. Such as the transition from E1 to E3, because the particle is unstable at the high energy level of E3, it will quickly fall to the metastable state E2 in a non-radiative transition process. At this energy level, the particles have a relatively long survival life. Due to the continuous excitation of the pump light source, the number of particles at the E2 energy level will continue to increase, and the number of particles at the E1 energy level will increase. In this way, the population inversion distribution is realized in the erbium-doped fiber, and the conditions for learning optical amplification are available.
When the input signal photon energy E=hf is precisely equal to the energy level difference between E2 and E1, E2-E1=hf, the particles in the metastable state will transition to the ground state E1 in the form of stimulated radiation. The radiation and the input The photons in the signal are identical to the photons, thus significantly increasing the photons' number, making the input optical signal become a strong output optical signal in the erbium-doped fiber, realizing the direct amplification of the optical signal.

2. System diagram and basic device introduction
2.1. The schematic diagram of the L-band optical fiber amplifier system is as follows:

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2.2. The schematic diagram of the ASE light source system for spontaneous emission of erbium-doped fiber is as follows:

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Device introduction

1.ROF -EDFA -HP High Power Erbium Doped Fiber Amplifier

Parameter Unit Min Typ  Max
Operating wavelength range nm 1525   1565
Input signal power range dBm -5   10
Saturation output optical power dBm     37
Saturation output optical power stability dB     ±0.3
Noise index @ input 0dBm dB   5.5 6.0
Input optical isolation dB 30    
Output optical isolation dB 30    
Input return loss dB 40    
Output return loss dB 40    
Polarization dependent gain dB   0.3 0.5
Polarization mode dispersion ps     0.3
Input pump leak dBm     -30
Output pump leak dBm     -30
Operating voltage V( AC ) 80   240
Fiber type  

SMF-28

Output interface  

FC/APC

Communication interface  

RS232

Package size Module mm

483×385×88(2U rack)

Desktop mm

150×125×35

2.ROF -EDFA -B erbium-doped fiber power amplifier

Parameter

Unit

Min

Typ

Max

Operating wavelength range

nm

1525

 

1565

Output signal power range

dBm

-10

   
Small signal gain

dB

 

30

35

Saturation optical output range *

dBm

 

17/20/23

 
Noise figure **

dB

 

5.0

5.5

Input isolation

dB

30

   
Output isolation

dB

30

   
Polarization independent gain

dB

 

0.3

0.5

Polarization mode dispersion

ps

   

0.3

Input pump leak

dBm

   

-30

Output pump leak

dBm

   

-40

Operating voltage

module

V

4.75

5

5.25

desktop

V( AC )

80

 

240

Optical  fiber  

SMF-28

Output  interface  

FC/APC

Dimensions

module

mm

90×70×18

desktop

mm

320×220×90

           

3. ROF -EDFA -P model  Erbium doped fiber amplifier

Parameter

Unit

Min

Typ

 Max

Operating wavelength range

nm

1525

 

1565

Input signal power range

dBm

-45

   
Small signal gain

dB

 

30

35

Saturation optical power output range *

dBm

 

0

 
Noise index **

dB

 

5.0

5.5

Input optical isolation

dB

30

   
Output optical isolation

dB

30

   
Polarization dependent gain

dB

 

0.3

0.5

Polarization mode dispersion

ps

   

0.3

Input pump leak

dBm

   

-30

Output pump leak

dBm

   

-40

Operating Voltage

Module

V

4.75

5

5.25

Desktop

V( AC )

80

 

240

Fiber type  

SMF-28

Output Interface  

FC/APC

Package size

Module

mm

90*70*18

Desktop

mm

320*220*90