Matt's Blog

Today on the archive - photonic crystal fibres

Tue Aug 15 08:41:53 BST 2006

  • [physics/0608142]

    • Title: Nonlinear photonic crystal fibres: pushing the zero-dispersion toward the visible
    • Authors: Kunimasa Saitoh, Masanori Koshiba, Niels Asger Mortensen
    • Abstract: The strong waveguide dispersion in photonic crystal fibres provides unique opportunities for nonlinear optics with a zero-dispersion wavelength $\lambda0$ far below the limit of ~1.3 micron set by the material dispersion of silica. By tuning the air-hole diameter d, the pitch Lambda, and the number of rings of air holes N, the strong waveguide dispersion can in principle be used to extend lambda0 well into the visible, albeit to some extend at the cost of multimode operation. We study in detail the interplay of the zero-dispersion wavelength, the cut-off wavelength lambda_c, and the leakage loss in the parameter space spanned by d, Lambda, and N. As a particular result we identify values of d (~500 nm) and Lambda (~700 nm) which facilitate the shortest possible zero-dispersion wavelength (~700 nm) while the fibre is still single-mode for longer wavelengths.
  • [physics/0608143]

    • Title: Photonic crystal fibres: mapping Maxwell's equations onto a Schrodinger equation eigenvalue problem
    • Authors: Niels Asger Mortensen
    • Abstract: We consider photonic crystal fibres (PCFs) made from arbitrary base materials and introduce a short-wavelength approximation which allows for a mapping of the Maxwell's equations onto a dimensionless eigenvalue equations which has the form of the Schrodinger equation in quantum mechanics. The mapping allows for an entire analytical solution of the dispersion problem which is in qualitative agreement with plane-wave simulations of the Maxwell's equations for large-mode area PCFs. We offer a new angle on the foundation of the endlessly single-mode property and show that PCFs are endlessly single mode for a normalized air-hole diameter smaller than ~0.42, independently of the base material. Finally, we show how the group-velocity dispersion relates simply to the geometry of the photonic crystal cladding.

[physics]

[permlink]

code (24)

erlang (5)
ideas (19)
lisp (1)
me (11)
notes (4)
ocaml (1)
physics (45)
qo (7)
unix (6)
vim (3)