Photonic crystal waveguides and systems using such waveguides

摘要

In general, in one aspect, the invention features an apparatus that includes a photonic crystal fiber configured to guide a mode of electromagnetic radiation at a wavelength, lambda, along a waveguide axis. The fiber includes a core extending along the waveguide axis, and a confinement region extending along the waveguide axis and surrounding the core. The confinement region includes alternating layers of a first and a second dielectric material having thicknesses d₁ and d₂ and different refractive indices n₁ and n₂, respectively. The thickness of at least one of the alternating layers of the first material_differs from thickness d₁^QW or at least one of the alternating layers of the second material_differs from thickness d₂^QW, where d₁^QW and d₂^QW correspond to a quarter-wave condition for the two dielectric materials given by d₁^QW=lambda/(4{square root}{square root over (n₁²-1)}) and d₂^QW=lambda/(4{square root}{square root over (n₂²-1)}), respectively. The photonic crystal fiber has an attenuation for the guided mode at the wavelength lambda that is reduced by a factor of about two or more relative to an attenuation for a reference fiber that is identical to the photonic crystal fiber except that the reference fiber has alternating layer thicknesses corresponding to the quarter-wave condition.