Optical Fiber Amplifier

Abstract

The optical fiber amplifier allows O/O conversion for direct optical amplification instead ofthe conventional O/E and E/O conversion.
The amplifier for 1. 55 μm optical signal is compactly composed by Er³⁺ -doped fiber andother optical components. Amplification and oscillation properties of the amplifier are mainlydependent on the Er³⁺ doping concentration, the co-dopant, fiber length, and performance of the pumping power source. An optimized fiber, for use within the optical amplifier, has a gainof 40dB and a conversion efficiency of 85% from the incident pumping power to the amplifiedsignal power. Amplification properties also depend on the characteristics of the optical signal.
With these advantages, the amplifier has brought expandability and flexibility to opticalcommunication systems, making great impact on optical communications. It is applicable topost-amplifiers for enhancing optical signal output, low-noise pre-amplifiers to improve thesensitivity of the signal receiver, in-line amplifier transmission lines and multi-wavelength signalsystems. It is also expected for wider use in long-haul transmission systems, subscriber systems, and future soliton communications.