Artificial control of optical gain polarization by stacking quantum dot layers

Abstract

Polarization insensitivity of InAs∕GaAs quantum dot (QD) optical amplifier has been demonstrated by controlling the dot shape. The height of the QD has been controlled by stacking closely InAs islands to form a columnar QD. Room-temperature polarized amplified spontaneous emission from the columnar QDs has been investigated by using variable stripe-length method. With increasing the aspect ratio, transverse-magnetic-mode-dominant optical gain has been achieved. We obtained almost polarization insensitive optical gain for QDs with seven stacking layers.