Studying refractive index changes and phase recovery of tapered quantum-dot semiconductor optical amplifiers

In this paper, the effects of using tapered waveguides on the refractive index and the phase recovery of quantum-dot semiconductor optical amplifiers (QD-SOAs) are studied for the first time, to the best of our knowledge. Although the gain of the device is impressively improved through tapering the waveguide, but it is shown that the refractive index of the device and so the relative phase of the signal are changing more considerably as the signal´s being amplified. Moreover, device´s phase recovery is noticeably slower than the recovery obtained for the generic one.