Amplified spontaneous emission and gain characteristics of Fabry-Perot and traveling wave type semiconductor laser amplifiers

Semiconductor laser amplifiers are investigated with respect to amplified spontaneous emission power and gain characteristics. The influence of the spontaneous emission coefficient, input power, and facet reflectivity on amplifier saturation characteristics is analyzed. It is shown that a small β, zero reflectance device has advantageous properties in terms of high gain and output power at the 3-dB compression point. The low reflectance contributes to a slow saturation, whereas a low β means a larger optical model and hence lower intensities and less saturation for a given output power or gain