Testing apparatus for optical devices

An apparatus, comprising:

• a transparent wafer carrier to hold a wafer of bottom-emitting or bottom-detecting optical devices,
• wherein the transparent wafer carrier comprises a set of holes in an area of the transparent wafer carrier for holding the wafer;
• a lower transparent plate;
• and
• a structure supporting the transparent wafer carrier and the lower transparent plate to form a cavity bounded by the transparent wafer carrier, the lower transparent plate, and the structure,
• wherein the structure comprises an opening in fluid communication with the cavity,
• wherein applying suction through the opening, via the cavity and the set of holes, holds the wafer flat on the transparent wafer carrier, and
• wherein an optical path, between a bottom-emitting or bottom-detecting optical device of the bottom-emitting or bottom-detecting optical devices of the wafer and a testing device, passes through the transparent wafer carrier, the cavity, and the lower transparent plate.

A method for holding an optical wafer under test, comprising:

• positioning an upper plate on a structure to form a cavity bounded by the upper plate, a lower plate, and the structure,
• wherein the upper plate comprises a set of holes in fluid communication with the cavity;
• positioning the optical wafer on the upper plate over the set of holes;
• applying, after positioning the upper plate and positioning the optical wafer, vacuum through an opening of the structure to create suction, via the cavity and the set of holes, thereby holding the optical wafer flat on the upper plate;
• and
• performing, after applying vacuum and by a testing device, at least one of detecting light traveling from the optical wafer through the upper plate and the lower plate or emitting light through the lower plate and the upper plate to the optical wafer;
• wherein the upper plate and the lower plate are transparent for the light travelling to or emitted from the optical wafer.