Abstract: An optical signal switch identifies the routing of each optical packet, directs each packet arriving at any input to the output corresponding to the routing, and includes delay lines through which the optical signals pass selectively. The switch has three stages: a first stage directing each optical packet received at an input to a chosen delay line, a second stage coupled to the output of the delay lines to direct the optical packets selectively to the output corresponding to the determined routing, and an output third stage.

Abstract: A photorefractive device intended to be exposed to a marking radiation which is provided so as to create a grating of interference fringes in the device and to a reading radiation diffracted by the created grating. The device includes an electro-optical material having a quantum well structure (24) and formed in an intrinsic semi-conductor matrix (22, 24) and, on both sides of the material in the semi-conductor matrix, suitable means (28, 30) to trap, both parallel to the axis of the structure and perpendicular to this axis, free carriers generated by the marking radiation.