The most common amplifiers found on the market are:
- The Erbium-Doped Fiber Amplifier (EDFA), which generally uses a single-mode fiber with an erbium-doped core. The advantages of EDFA are high gain, a wide bandwidth and high-output power.
- The Raman amplifier is mainly used to amplify signal levels. It has the advantage of having a wide operating wavelength range, constant optical gain, and noise reduction.
- Other active dopants can be used, for example, with the addition of ytterbium to obtain an Erbium/Ytterbium amplifier (EYDCF).
As the requirements for telecommunications networks continue to grow, optical amplifiers require more power to transmit the information over a long distance and an increasingly wider bandwidth to optimize the transmission speed.
The choice of optical fiber plays an important part in the design of an effective optical amplifier. Low background loss and high QCE are, in fact, key parameters to take into consideration.