Applications of EDFA

 

EDFA

Following are the typical application of Erbium doped fiber amplifiers.

 

1. Power Amplifiers

 

2. In-Line Amplifiers

 

3. Pre Amplifiers

 

4. Loss Compensation in Optical Networks

 

Power Amplifier:

Power amplifiers (also called booster amplifiers) are placed directly after the optical transmitter. In this application, EDFA’s need to be able to take a large input signal and provide maximum possible output level. The noise is not a major concern at this stage as the incoming signal has a large signal to noise ratio. Typical EDFA power amplifiers have an output of around 100mW.

 

In-Line Amplifier:

The in-line amplifier (also called in-line repeater) takes a small input signal and boost its for retransmission down the fiber and thus it replaces the repeater within a long communication line. At this stage, noise is a major concern because the signal is weak.

 

Pre-Amplifier:

Modern telecommunication systems are pushing the practical limits of receiver sensitivities. In past, -30dBm at 622Mbps was adequate, but today customers demand sensitivities of –40dBm or –45dBm. These requirements are met by adding optical amplifiers prior to receiver called “Preamplifier”. For this application, the noise added by EDFA is critical because the incoming signal to noise ratio (SNR) is at minimum so the amplifier needs to add minimal noise at this point.

 

Loss Compensation in Optical Networks:

In this application, an EDFA is used as a power booster at the transmitter output. This followed by an 8-to-1 optical splitter. Optical splitter has a nominal optical insertion loss of 10dB so if the transmitter has an optical output of 10dBm, the splitter outputs without EDFA would be 0dBm. With the EDFA inserted before the optical splitter, the power into the splitter could be increased to perhaps 19dBm, allowing each of the 8 output legs to provide +9dBm, each nearly equal to transmitter power.