Mechanical properties of calcium silicate hydrate under uniaxial and biaxial strain conditions: a molecular dynamics study.

Calcium silicate hydrate (C-S-H) is the main hydration product of cementitious materials, often experiencing complex stress conditions in practical applications. Therefore, reactive molecular dynamics methods were used to investigate the mechanical response of the atomistic structure of C-S-H under various uniaxial and biaxial strain conditions. The results of uniaxial simulations show that C-S-H exhibits mechanical anisotropy and tension-compression asymmetry due to its layered atomistic structure.

Enhancement of the pockels effect in photonic crystal modulators through slow light.

We report a photonic crystal (PhC) optical modulator operating in the optical C band (1530-1565 nm) using barium titanate epitaxial thin films as the electro-optic (EO) medium. The PhC has hexagonal lattice symmetry and an extinction ratio of 9 dB. Due to the slow light enhancement of the EO coefficient near the PhC band edge, the driving electrode can be as short as a one millimeter.

Silicon/III-V laser with super-compact diffraction grating for WDM applications in electronic-photonic integrated circuits.

We have demonstrated a heterogeneously integrated III-V-on-Silicon laser based on an ultra-large-angle super-compact grating (SCG). The SCG enables single-wavelength operation due to its high-spectral-resolution aberration-free design, enabling wavelength division multiplexing (WDM) applications in Electronic-Photonic Integrated Circuits (EPICs). The SCG based Si/III-V laser is realized by fabricating the SCG on silicon-on-insulator (SOI) substrate.

Design of temperature-independent arrayed waveguide gratings based on the combination of multiple types of waveguide.

We develop a design theory for a temperature-independent arrayed waveguide grating (TI-AWG) based on the combination of multiple types of waveguide. Each type of waveguide has a path-length difference between adjacent arrayed waveguides, and the path-length difference ratio is introduced as tuning parameter. A TI-AWG with Si wire and slot waveguides is given as an example.