Semiconductor optical amplifiers for future optical networks

This work describes the principal applications of SOAs in optical communication systems. They can be classified into three areas: (a) postamplifier or booster amplifier to increase transmitter laser power, (b) in-line amplifier to compensate for fiber and other transmission losses in medium and long-haul links and (c) preamplifier to improve receiver sensitivity. SOAs are used in both linear and nonlinear modes of operation. The development of photonic integrated circuits has made feasible the deployment of complex SOA functional subsystems. In WDM channels applications, linear gain SOAs can be obtained. They have demonstrated their multifunctional capability by combining optical amplification with either modulation or in-line photodetection. The major advantages of SOA's are their capability to operate as multifunctional devices, their compactness, and their potentially low cost.

Many of the advances in optical networks have been made possible by the optical amplifiers where their incorporation into optical communication links can improve system performance and reduce costs. Optical amplifiers can be divided into two classes: optical fibre amplifiers and semiconductor optical amplifiers (SOAs). The optical fibre amplifiers such as Erbium Doped Fibre Amplifier (EDFA) are mainly used for in-line amplification to compensate fibre losses. However, the SOA is showing great promise for use in evolving optical communication networks thanks to their capability to operate as multifunctional devices, to their compactness, and their potentially low cost.