Patent ID: 7486707

Claim:
An optical delay module for lengthening the propagation path of a light beam, comprising: a first spherical mirror and a second spherical mirror, said first spherical mirror and said second spherical mirror having equal radii of curvature, a common axis of symmetry passing through a center of each said first and second mirrors and where each of said first and second mirrors are symmetric about said axis; each of said first and second mirrors being situated opposite one another at a mirror distance from one another which corresponds to said radii of curvature of said first and second mirrors; a coupling-in area for coupling said light beam into a space between said first and second mirrors, and a coupling-out area for coupling the light beam out of said space between said first and second mirrors, said propagation path of said light beam between said coupling-in area and said coupling-out area corresponding at least approximately to quadruple said mirror distance; at least one optical arrangement arranged between said first and second mirrors, said optical arrangement being arranged to transfer said light beam without masking out of beam parts between said first and second mirrors in such a way that said propagation path of said light beam between said coupling-in area and said coupling-out area corresponds approximately to 2N times said mirror distance, where N is an integer >2.