Apparatus comprising at least one optical device (106) optically coupled to at least one waveguide (111) on an optical chip (100), characterized in that: (i) the optical device (106) is optically aligned with the waveguide (111) by aligning means (114, 116); (ii) the aligning means (114, 116) comprises at least one male member (114) and at least one female (116) member which locate together; (iii) one of the male member (114) and the female member (116) is positioned on the optical chip (100); (iv) the other one of the male member (114) and the female member (116) is positioned on a capping chip (102); and (v) the apparatus includes a mirror (108) for reflecting light from the optical device (106) to the waveguide (111).