Ultrabroadband and independent polarization of optical amplification with InGaAs-based indium-rich cluster quantum-confined structure

Abstract

This Letter reports polarization-independent optical amplification over an ultrabroad spectral range by semiconductor optical amplifiers. The technique uses an InGaAs-based indium-rich cluster (IRC) quantum-confined structure as the active medium and obtains comparable optical gain for both transverse electric (TE) and transverse magnetic (TM) polarization modes in the spectral ranges of 905–1005 and 905–970 nm, respectively. The device thus provides independent optical amplification for TE and TM polarizations over a common bandwidth of 65 nm. The difference between the amplified intensities of TE and TM modes is <0.5 dB. These results are attributed to the special emission mechanism of the IRC quantum-confined structure, which differs from that of conventional quantum wells or quantum dots. A preliminary analysis of this mechanism is provided.