All-optical self-routing of 40 Gb/s DPSK packets

We demonstrate a self-routing all-optical circuit for switching 40 Gb/s DPSK packets. In our scheme, an all-optical header processor feeds a set-reset flip-flop that drives a coherent wavelength converter. We report an overall limited power penalty

Simultaneous beam steering of multiple signals based on optical wavelength-selective switch

A novel, photonics-based scheme for the independent and simultaneous beam steering of multiple radio frequency signals at a wideband phased-array antenna is presented. As a proof of concept, a wavelength-selective switch (WSS) is employed both as a wavelength router to feed multiple antenna elements and as a tunable phase shifter to independently control the phase of each signal at any antenna element. In the experiment, two signals at 12.5 and 37.5 GHz are simultaneously fed to the four output ports of the WSS with independent and tunable phase shifts, emulating the independent steering of two signals in a four-element phased-array antenna. The results confirm the precision and flexibility of the proposed scheme, which can be realized both with bulk components or resorting to photonic integrated circuits, especially for wide-band applications. The architecture for a possible integrated implementation of the proposed solution is presented, employing a structure based on micro-ring resonator. Starting from these results, the feasibility of an integrated version of the presented architecture is also considered. The proposed photonic integrated circuit realizing the beam-forming network might be based on tunable true-time delay, as well as on phase shift through micro-ring resonators, and could be conveniently implemented with CMOS-compatible silicon technology.</jats:p

Enantioselective synthesis of pseudopeptides incorporating gamma-methylene derivative of 2,6-diaminopimelic acid. Part 6

An efficient enantioselective synthesis of pseudotripeptides, incorporating 2,6-diamino-4-methylene-1,7-heptandioic acid residue, has been accomplished starting from the glycine derived chiral synthon (obtained from L-valine). The absolute configuration of new stereocenters was assigned on the basis of 1H-NMR spectra. The geometry was deduced on the basis of 1H-NMR parameters and IR spectra