PHOTONIC CRYSTAL WAVEGUIDES AND SYSTEMS USING SUCH WAVEGUIDES

In general, in one aspect, the invention features an apparatus that includes a photonic crystal fiber (200, 900) configured to guide a mode of electromagnetic radiation at a wavelength, .lambda., along a waveguide axis. The fiber includes a core (210) extending along the waveguide axis, and a confinement region (220, 910) extending along the waveguide axis and surrounding the core (210). The confinement region (220, 910) includes alternating layers (211-219, 920-922) of a first and a second dielectric material having thicknesses d1and d2and different refractive indices n1and n 2, respectively. The thickness of at least one of the alternating layers of the first material differs from thickness d1QWor at least one of the alternating layers of the second material differs from thickness d2QW,where d1QWand d2QWcorrespond to a quarter-wave condition for the two dielectric materials given by Formula (I) and Formula (II), 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.