Optical Fiber Amplifier – EDFA (Erbium-doped Fiber Amplifier) for FTTH WDM system

Optical Fiber Amplifier Basics
When transmission over long distance, the optical signal must be amplified many times in between owing to the signal loss from fiber attenuation, connectivity losses, fiber splicing losses, etc. Before optical fiber amplifier is invented, the optical signal need to be first converted into electrical signal, amplified, and then converted back to optical signal again(also called the process as OEO). The process is very complicated and expensive. Optical fiber amplifier has been invented that can amplify signals directly, this process is significantly cheaper and started a fiber optic revolution. There are three fiber optic amplifier types: EDFA, Raman amplifier and semiconductor optical amplifier(SOA). 

Optical fiber amplifiers serve as an integrated part of long haul data transmission. The most prominent feature of fiber amplifier is that the device can amplify optical signal directly without need to convert the signal into an electrical one before amplifying. EDFA (Erbium-doped Fiber Amplifier) is one type of many different optical amplifiers that can achieve signal amplification over long-haul optical communication transmission.

What Is EDFA Fiber Amplifier?
The amplifying medium is a glass optical fiber doped with erbium ions. The erbium-doped fiber gain medium amplifies light at wavelengths that are in the neighborhood of 1550 nm—the optical wavelengths that suffer minimum attenuation in optical fibers. EDFA, Erbium-doped Fiber Amplifier, is the most deployed optical amplifier in the FTTH WDM system that uses the Erbium-doped fiber as optical amplification medium to directly enhance the signals. EDFA works best in the range 1530 to 1565 nm, and it possesses low noise and can amplify many wavelengths simultaneously, making it the fiber amplifier of choice for most applications in optical communications. 

How Does EDFA Work?
Basically, EDFA consists of a length of EDF(Erbium doped fibre), a pump laser, and a WDM combiner. The WDM combiner is for combining the signal and pump wavelength, so that they can propagate simultaneously through the EDFA. The lower picture shows a more detailed schematic diagram of EDFA.

                                                         EDFA working priciple

The optical signal, such as a 1550nm signal, enters an EDFA amplifier from the input. The 1550nm signal is combined with a 980nm pump laser with a WDM device. The signal and the pump laser pass through a length of fiber doped with Erbium ions. The 1550nm signal is amplified through interaction with the doping Erbium ions. This action amplifies a weak optical signal to a higher power, effecting a boost in the signal strength. 

Why EDFA Fiber Amplifier Is Essential for FTTH WDM System?
Nowadays, EDFA optical amplifier rises as a preferable option for signal amplification method for DWDM systems, owing to its low-noise and insensitive to signal polarization. Besides, EDFA deployment is relatively easier to realize and more affordable compared with other signal amplification methods.


BAUDCOM EDFAs have high pump power utilization (>50%) Directly and simultaneously amplify a wide wavelength band (>80nm) in the 1550 nm region, with a relatively flat gain. Flatness can be improved by gain-flattening optical filters. Gain in excess of 50 dB. Low noise figure suitable for long haul applications.

BAUDCOM FTTH WDM EDFA fiber amplifier is a low noise high-performance Er Yb codoped fiber amplifier designed to extend the distance in FTTH WDM optical infrastructure. Each output built-in CWDM (1310/1490/1550) wavelength division multiplexer. Conveniently multiplex the data stream of OLT and ONU to the fiber amplifier output by 1310nm and 1490nm optical connector. Thus reduced the equipment quantity, improved the system indexes and reliability. It is the ideal equipment for FTTx network, provides a flexible and low cost solution for the integration of three networks and the FTTH.

 EDFA WDM application

Post time: 2019-12-22


Lomoveishiy – Finland

I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!

Raymond – USA

Great experience – units worked straight out of the box – just needed plug in cables and we were done. I also like the possibility to enable jumbo frames, while we do not have a need for this feature at the current moment it’s great to have this option.

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