Provided herein is a semiconductor package and method of forming the same. The semiconductor package has a cap including a first window wafer with a first face and opposing second face, a second window wafer, and a perforated spacer wafer with through-holes extending therethrough. The first and second faces of the first window wafer are mutually parallel and at least one face includes an antireflective surface. The spacer wafer is disposed between the first and second window wafers with the first and second window wafers bonded to opposing faces of the spacer wafer. The window wafers and spacer wafer together define a cavity in the cap. An edge-emitting laser diode is disposed on a submount and configured to direct a laser beam at normal incidence to the first face of the first window wafer. The cap is mounted on the submount with the edge-emitting laser diode enclosed in the cavity.