US Patent 7272161 Epitaxial layer for laser diode ridge protection

A semiconductor laser formed from a semiconductor wafer has an active layer, at last two optical cladding layers, and a ridge waveguide. A ridge top surface of the ridge waveguide is deposited from a first surface of the semiconductor laser wafer by a first height. A plurality of semiconductor mesas are formed on the semiconductor laser wafer and have mesa top surfaces disposed from the first surface by a second height greater than the first height so that the plurality of semiconductor mesas shield the ridge waveguide from mechanical damage.