Semiconductor optical amplifiers for all transmission wavelength bands

Summary form only given. An overview is presented of the progress in design and characteristics of semiconductor optical amplifiers (SOA) for 1310, 1400 and 1550 nm operation in fiber optical transmission systems. The technology and performance of SOAs will be discussed with respect to optical gain, noise figure, saturation output power and polarization (in-) dependent behavior. The use of both strained quantum wells and bulk tensile material will be discussed in view of obtaining polarization independent behavior. Gain clamping in SOAs has been shown to improve the linearity performance especially for analogue signal transmission. The SOA technology has been demonstrated for optical pre-amplification, in-line application and optical booster applications. DWDM experiments using SOAs in up to 20 Gbit/s systems in short- and medium-distance transmission will be highlighted. Also, SOAs have been used in optical demultiplexing from 40 Gbit/s down to 10 Gbit/s RZ signals using its phase properties and in integrated photonic devices like multiwavelength lasers.