Influence of the confinement factor on the wavelength-dependent output properties of a tapered traveling-wave semiconductor amplifier

We analyze the influence of the confinement factor on the output properties of a tapered traveling-wave semiconductor amplifier as a function of the wavelength of the input field and current injected into the amplifier. The interaction of the optical field with the amplifying medium is described by means of a susceptibility function taking into account both the gain and the carrier-induced antiguiding effect, while the beam propagation method is used to describe the evolution of the field along the amplifier. We find that, for the same input power, devices with lower optical confinement factors allow for the same output optical power with better beam quality and higher saturation power than devices with higher optical confinement factor, in agreement with the available experimental results.