laser of the present invention may be fabricated by any conventional method by which active and blocking regions may be formed wherein their refractive index difference at the fundamental frequency is less than about 0 029 provided below as an example is a fabrication method for a mesa buried heterostructure distributed feedback laser which may be used to construct a laser according to embodiments of the present invention a double heterostructure is grown over conventional first order distributed feedback gratings that are etched into a substrate the substrate may be for example inp the double heterostructure may be grown by a variety of epitaxial techniques such as for example liquid phase epitaxy hybrid vapor phase epitaxy and metalorganic vapor phase epitaxy the double heterostructure may consist of a plurality of layers an oxide layer such as silicon dioxide for example is deposited over the surface of the double heterostructure stripes are photolithographically patterned in a direction perpendicular to the gratings the silicon dioxide or analogous layer serves as both an etch mask during mesa etching and a growth mask during blocking layer growth which is performed using metalorganic vapor phase epitaxy mesas are chemically etched to the desired width for example 1 0 3 0 u03bcm the mesas that are formed are vertical walled for several microns below the surface thus providing good correspondence between the mesa width and the active width after etching semi insulating blocking layers are regrown around the mesas by selective metalorganic vapor phase epitaxy after metalorganic vapor phase epitaxy blocking layer regrowth the sio 2 is etched away.