Optical alignment apparatus, consisting of an optical element (28) having a curved surface (29), and an optical bench (22), including a mounting surface (21) for mounting of an optical component (24, 44) thereon. The optical bench has an opening (26) formed in the mounting surface, the opening having a size and shape suitable to engage the curved surface of the optical element so as to permit alignment of the optical element with the optical component by relative rotation of the optical element within the opening while the curved surface is engaged by the opening.