The performance of four passive optical network topologies in implementing multi-user quantum key distribution is compared, using 3 protocols proposed by quantum cryptography (B92, EPR, SSP). The networks considered are the passive-star network, the optical-ring network based on the Sagnac interferometer, the wavelength-routed network, and the wavelength-addressed bus network . An analysis of the quantum bit-error rate and sifted key rate for each of these topologies is used to determine their suitability for providing quantum key distribution-service to networks of various sizes. The efficiency of the three considered protocols is also determinated.
We discuss an electro-optical device that acts as a multifunction logical gate based on a BSO photorefractive crystal. It is an easily reconfigurable device which can perform different logic functions such as AND, OR, NOT, NOR using the same configuration and changing only the controlling parameters.
An all-optical cryptographic device for security applications, based on the properties of soliton beams, is presented. It is able to codify a given bit stream of optical pulses, changing their phase and their amplitude as a function of one or more encryption serial keys that merge with the data stream, generating an incomprehensible stream. Its great advance is represented by its capability of encrypting in real time, without slowing the data flow that can be transmitted with its original velocity.
We present an all-optical cryptographic device for security applications, based on the properties of soliton beams. It is able to codify a given bit stream of optical pulses, inverting at will their order, to make the stream not understandable. Its great advance is represented by its capability of encrypting in real time, without slowing the data flow that can be transmitted with its original velocity.
We present a device that is capable of switching a sequence of equally space pulses between two or more outputs, according to the switching information carried from the first pulse, that behaves as an addresser. The device acts as an all-optical router and it is based on the properties of a soliton beam in a transverse refractive index profile. We further study the interaction force between solitons.
Spatial solitons are self-trapped optical beams that propagate without changing their spatial shape, since the diffraction and the nonlinear refraction balance each other in a self-focusing . In this paper we study the behavior of a soliton beam in a waveguide which, in the plane between the cladding and the substrate, has a distribution of refractive index that follows a trapezoidal curve considering the possibility that the soliton propagates in an oblique direction.
A device that is capable of addressing an input pulse through different exits is presented. The controlling parameter is constituted by the intensity of the input beam. The scheme is based on an interesting property of a soliton in a waveguide with transverse gaussian refractive index profile.
A device capable of addressing an input pulse through different outputs is presented. The controlling parameter is the power of the input beam. The device is characterized by a 100% transferring efficiency and a short switching time.