We demonstrate experimentally all-optical switching on a silicon chip at telecom wavelengths. The switching device comprises a compact ring resonator formed by horizontal silicon slot waveguides filled with highly nonlinear silicon nanocrystals in silica. When pumping at power levels about 100 mW using 10 ps pulses, more than 50% modulation depth is observed at the switch output. The switch performs about 1 order of magnitude faster than previous approaches on silicon and is fully fabricated using complementary metal oxide semiconductor technologies.

No abstract

Abstract:We study the reflection properties of squeezing devices based on transformation optics. An analytical expression for the angle-dependent reflection coefficient of a generic three-dimensional squeezer is derived. In contrast with previous studies, we find that there exist several conditions that guarantee no reflections so it is possible to build transformation-opticsbased reflectionless squeezers. Moreover, it is shown that the design of antireflective coatings for the non-reflectionless case can be reduced to matching the impedance between two dielectrics. We illustrate the potential of these devices by proposing two applications in which a reflectionless squeezer is the key element: an ultra-short perfect coupler for high-index nanophotonic waveguides and a completely flat reflectionless hyperlens. We also apply our theory to the coupling of two metallic waveguides with different cross-section. Finally, we show how the studied devices can be implemented with non-magnetic isotropic materials by using a quasiconformal mapping technique. 3432-3434 (2007). 18. D. P. Gaillot, C. Croënne, F. Zhang, and D. Lippens, "Transformation optics for the full dielectric electromagnetic cloak and metal-dielectric planar hyperlens," N. ©2011 Optical Society of America

A compact waveguide crossing structure with low transmission losses and negligible crosstalk is demonstrated for silicon-on-insulator circuits. The crossing structure is based on a mode expander optimized by means of a genetic algorithm leading to transmission losses lower than 0.2 dB and crosstalk and reflection losses below 40 dB in a broad bandwidth of 20 nm. Furthermore, the resulting crossing structure has a footprint of only 6x6 microm(2) and does not require any additional fabrication steps.

The nanoparticle volume fraction employed in the figures and text was 3.4%, rather than the erroneously quoted 0.8%. The abscissa in Figures 1 and 2 should say nanoparticle radius and not nanoparticle diameter. We also note that the experimentally adjusted value of δ 3 employed in eq 5 is 38.8 Å 3 , rather than the actual geometrical volume. None of the conclusions in the paper is affected by the previous corrections. We thank Shidong Wang and Ivana Savic ´for pointing out these errata.