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Subwavelength-diameter silica wires for low-loss optical wave guiding


Silica waveguides with diameters larger than the wavelength of transmitted light are widely used in optical communications, sensors and other applications1,2,3. Minimizing the width of the waveguides is desirable for photonic device applications, but the fabrication of low-loss optical waveguides with subwavelength diameters remains challenging because of strict requirements on surface roughness and diameter uniformity4,5,6,7. Here we report the fabrication of subwavelength-diameter silica ‘wires’ for use as low-loss optical waveguides within the visible to near-infrared spectral range. We use a two-step drawing process to fabricate long free-standing silica wires with diameters down to 50 nm that show surface smoothness at the atomic level together with uniformity of diameter. Light can be launched into these wires by optical evanescent coupling. The wires allow single-mode operation, and have an optical loss of less than 0.1 dB mm-1. We believe that these wires provide promising building blocks for future microphotonic devices with subwavelength-width structures.

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Figure 1: The second step in the fabrication process of silica submicrometre- and nanometre wires (SMNWs).
Figure 2: Electron micrographs of SMNWs.
Figure 3: Micromanipulation and flexibility of SMNWs.
Figure 4: Optical characterization of SMNWs.


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We thank Y. Lu, Z. Han and B. Tull for assistance in SEM and TEM imaging, and L. Liu and X. Chen for help with numerical simulations. This work was supported by the US National Science Foundation and by the National Natural Science Foundation in China. T.L. acknowledges support from the Centre for Imaging and Mesoscale Structures at Harvard University.

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Correspondence to Eric Mazur.

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Tong, L., Gattass, R., Ashcom, J. et al. Subwavelength-diameter silica wires for low-loss optical wave guiding. Nature 426, 816–819 (2003).

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