This is the unspecified version of the paper.This version of the publication may differ from the final published version. A golden spiral photonic crystal fiber (GS-PCF) design is presented in which air holes are arranged in a spiral pattern governed by the golden ratio, where the design has been inspired by the optimal arrangement of seeds found in nature. The birefringence and polarization properties of this fiber are analyzed using a vectorial finite-element method. The fiber that is investigated shows a large modal birefringence peak value of 0.016 at an operating wavelength of 1.55 m and exhibits highly tuneable dispersion with multiple zero dispersion wavelengths and also large normal dispersion. The GS-PCF design has identical circular air holes that potentially simplify fabrication. In light of its properties, the GS-PCF could have application as a highly birefringent fiber and in nonlinear optics, and moreover the 2D chiral nature of the pattern could yield exotic properties. Permanent repository link

A rigorous modal solution approach, based on the numerically efficient finiteelement method (FEM), has been used to design and characterize a photonic crystal fiber (PCF) with a porous air core, which has the potential for use for low-loss guidance of terahertz (THz) waves. Here, for the first time, it is reported that a large fraction of the power that is also well confined in the waveguide can be guided in the low-loss air holes, thus to reduce the overall modal loss. This novel PCF design can readily be fabricated by use of a range of techniques including stack-and-draw, extrusion, and drilling.

This is the unspecified version of the paper.This version of the publication may differ from the final published version. Permanent repository link:

No abstract

Potassium hydrogen phthalate crystal is a good nonlinear optical system. Its electro-optic coefficient r 131 is measured for a wavelength of 670 nm and it is found to be of the order of that of urea crystal (1.06 pm V −1 ). The dispersion study for the effective Pockels coefficients r eff = r 113 − r 112 , is carried out for this crystal, and the electronic part of the electro-optic coefficient is shown to play an important role in the potassium hydrogen phthalate crystal. The electro-optical dispersion birefringence constant is found to be −1.11. Modulators based on KAP possess good figure of merits. The figure of merit that has been measured, corresponding to the wavelength of 670 nm is 9.5 pm V −1 .