Analysis of near- and far-field intensities in ZnO based heterostructure waveguides

Abstract

Analysis of near- and far-field intensities in a simple double heterostructure of ZnO/Mg x Zn1 − x O and hybrid double heterostructure of Al x Ga1 − x N/ZnO have been carried out at 375 nm wavelength. Near- and far-field intensity distribution along the junction plane has been studied as a function of mole fractions of Mg and Al for varying active layer thickness. The spread of the near- and far-field intensities has been estimated and articulated as full width at half maximum (FWHM). For near-field, FWHM was found to be decreasing nonlinearly with increase of Mg mole fraction in the simple heterostructure and increasing in a nonlinear manner with the increase of Al mole fraction in the hybrid heterostructure. FWHM deduced from our analysis was 0.355 µm for 7% and 0.156 µm for 27% Mg mole fraction. For the hybrid heterostructure, the FWHM values estimated were 0.1275 and 0.1397 µm, respectively. Confinement factor as a function of mole fractions and active layer thickness has been explored and it was found to be increasing with active layer thickness. The FWHM of far-field intensity shows a vertical divergence of 26○ and showed a minor variation with the active layer thickness. Finally, it is inferred from our analysis that confinement of the near-field was strongly influenced by the mole fraction and the active layer thickness while the far-field was weakly influenced.