Electrical performance of efficient quad-crescent-shaped Si nanowire solar cell.

The electrical characteristics of quad-crescent-shaped silicon nanowire (NW) solar cells (SCs) are numerically analyzed and as a result their performance optimized. The structure discussed consists of four crescents, forming a cavity that permits multiple light scattering with high trapping between the NWs. Additionally, new modes strongly coupled to the incident light are generated along the NWs.

Analysis of highly efficient quad-crescent-shaped Si nanowires solar cell.

Nanostructured semiconductor nanowires (NWs) present a smart solution for broadband absorption solar cells (SCs) with high efficiency and low-cost. In this paper, a novel design of quad crescent-shaped silicon NW SC is introduced and numerically studied. The suggested NW has quad crescent shapes which create a cavity between any adjacent NWs.

Orthogonal quasi-phase-matched superlattice for generation of hyperentangled photons.

A crystal superlattice structure featuring nonlinear layers with alternating orthogonal optic axes interleaved with orthogonal poling directions, is shown to generate high-quality hyperentangled photon pairs via orthogonal quasi-phase-matched spontaneous parametric downconversion. We demonstrate that orthogonal quasi-phase matching (QPM) processes in a single nonlinear domain structure correct phase and group-velocity mismatches concurrently. Compared with the conventional two-orthogonal-crystals source and the double-nonlinearity single-crystal source, the orthogonal QPM superlattice is shown to suppress the spatial and temporal distinguishability of the generated photon pairs by several orders of magnitude, depending on the number of layers.

Performance evaluation of hybrid DPSK-MPPM techniques in long-haul optical transmission.

In this paper, we evaluate the performance of hybrid differential phase shift keying-multipulse pulse position modulation (DPSK-MPPM) techniques in long-haul nonlinear-dispersive optical fiber transmission. An expression for the nonlinear interference variance is obtained analytically using the Gaussian noise (GN) model. We derive upper-bound expressions that take into account the fiber nonlinearity impact on the DPSK-MPPM system's performance for both bit- and symbol-error rates (BER and SER).