Polarization-resolved four-wave mixing spectroscopy is used to study interwell carrier dynamics in an alternating-strain multiquantum-well optical amplifier. The experimental data are found to be in good agreement with a simple model based on quantum capture/escape and diffusion processes. The results suggest that the interwell transport in this structure is mainly limited by carrier escape, an...

ABSTRACT In this paper, we studied the performance degradation of single-carrier and dual-carrier 100 Gb/s and 400 Gb/s systems due to optical filter cascade with 50 and 100/150 GHz channel spacing, respectively. Eye closure penalty (ECP) is used as a performance evaluation metric, where we use two types of filters: fiber Bragg grating (FBG) and thin-film filters (TFF). Simulation results indic...

We study accommodation of an excess charge carrier on long even-N polyynic oligomers C(N)H(2) due to displacements of the underlying carbon lattice and polarization of the surrounding solvent in the context of carrier self-localization into a polaronic state. Spatial patterns of bond-length alternation, excess charge and spin densities are compared as derived with Hartree-Fock and two hybrid de...

For airand spaceborne weather radars, which typically operate at frequencies of 10 GHz and above, attenuation correction is usually an essential part of any rain estimation procedure. For ground-based radars, where the maximum range within the precipitation is usually much greater than that from airor spaceborne radars, attenuation correction becomes increasingly important at frequencies above ...

The Coulomb scattering dynamics in graphene in energetic proximity to the Dirac point is investigated by polarization resolved pump-probe spectroscopy and microscopic theory. Collinear Coulomb scattering rapidly thermalizes the carrier distribution in k directions pointing radially away from the Dirac point. Our study reveals, however, that, in almost intrinsic graphene, full thermalization in ...

In this letter, we experimentally demonstrate direct correlation between efficiency droop and carrier overflow in InGaN/GaN green light emitting diodes (LEDs). Further, we demonstrate flat external quantum efficiency curve up to 400 A/cm in a plasma assisted molecular beam epitaxy grown N-polar double quantum well LED without electron blocking layers. This is achieved by exploring the superior ...

We investigated the high-carrier screening of macroscopic polarization fields in GaN quantum wells (QWs) using a variational wave function for electrons and holes. In particular, we studied of the influence of free-carrier screening on the photoluminescence (PL) energy emission and carrier lifetime in the QW. We show that the energy transition between electrons and holes are explained well by t...

Spin-polarized vertical-cavity surface-emitting lasers (spin-VCSELs) with birefringence-induced polarization oscillations have been proposed to generate desired photonic microwave signals. Here, we numerically investigate the generation of signals in an optically pumped quantum dot (QD) spin-VCSEL. First, influence intrinsic key parameters on period-one (P1) and properties is discussed. Second,...