Optical switching matrix and method of fabricating such a matrix

A method of fabricating an optical switching matrix, made from a semiconductor- or dielectric-based substrate, comprising:

• at least one set of optical input fibers (12) and at least one set of optical output fibers (14) oriented substantially perpendicular to each other,
• a set of moveable mirrors (13) placed at the intersections of the directions defined by the various optical fibers, each mirror being capable of moving in order to reflect a beam coming from an optical input fiber, bound for an optical output fiber,
• which comprises the steps consisting:
• on a first substrate wafer (2), in producing the set of moveable mirrors (13),
• on a second substrate wafer (21) , designed to cover the first wafer, in defining an overthickness zone (34), of dimensions substantially less than those of the matrix of moveable mirrors,
• in producing on said overthickness zone (34):
• a set of channels (38) at the locations of the beams coming from and bound for the optical fibers,
• a set of diagonal grooves (33) at the locations of the moveable mirrors,
• in covering the second wafer with a third wafer (40), so as to close said channels defined on the overthickness zone,
• in producing apertures (48) in the third wafer in order to open out the diagonal grooves (33) formed in the overthickness zone (34),
• in covering the first wafer (2) with the assembly formed by the second (21) and the third (40) wafer, such that, between the mirrors (13), the beams coming from and bound for the optical fibers are routed in the channels (38) defined in the overthickness zone and that the mirrors are capable of entering the housings defined by the diagonal grooves (33).