High-density integrated planar lightwave circuits using SiO/sub 2/-GeO/sub 2/ waveguides with a high refractive index difference

GeO/sub 2/-doped silica waveguides with a high refractive index difference of 1.5% are successfully fabricated on Si substrates. Their propagation loss, measured in 200-cm-long test circuits with a minimum curvature radius of 2 mm, is 0.073 dB/cm. The waveguides are used as high-density integrated planar lightwave circuits in 1/spl times/4 Mach-Zehnder (MZ) type multi/demultiplexers for optical frequency division multiplexing (FDM) transmission systems and in modified MZ type multi/demultiplexers with a ring resonator, which have a compact device size of 15/spl times/50 mm/sup 2/ and a frequency spacing of 10 GHz.<
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