Spectral Behavior and Dispersionless Propagation in Indium Phosphide Suspended Photonic Wires

The spectral behavior of suspended periodically tethered nanowires is investigated both theoretically and experimentally . The regularly spaced tethers act as a grating operating a codirectional coupling between the fundamental mode and the first-order transverse-electric (TE) mode for wide wires, and additionally a high order lateral distributed Bragg reflector effect in the case of narrow wires. A modal dispersion as low as partng/partlambda = 4 *10^-4 per nanometer on a 180-nm span is featured by the fundamental TE guided mode in the 1.5- mum wavelength domain, which provides neutral delay connections when integrating them within slow light photonic circuits.