Optical frequency comb-based multichannel parallel continuous-variable quantum key distribution.

Continuous-variable quantum key distribution (CVQKD) provides an approach for secure communication in optical fiber communication systems. However, its practical implementation has been hindered by low secret key bit rates that are usually limited to several bits/s to hundreds of kbits/s at distances of more than 25 kilometers. In this paper, we use a pair of optical frequency combs (OFCs) for both multiple parallel transmission and coherent reception, which assign multiple sub-channels involving multiple independent secret keys in a single fiber to increase the key bit rate.

Investigation on the intense fringe formation phenomenon downstream hot-image plane.

The propagation of a high-power flat-topped Gaussian beam, which is modulated by three parallel wirelike scatterers, passing through a downstream Kerr medium slab and free spaces is investigated. A new phenomenon is found that a kind of intense fringe with intensity several times that of the incident beam can be formed in a plane downstream the Kerr medium. This kind of intense fringe is another result in the propagation process of nonlinear imaging and it locates scores of centimeters downstream the predicted hot image plane.