Abstract: A method of manufacture of an optical waveguide structure including the steps of: providing a multilayer semiconductor wafer including a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer including aluminium and phosphorous; and etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.

Abstract: An optical waveguide structure including a III-V semiconductor substrate, a III-V semiconductor top layer, and an etch stop layer sandwiched therebetween, the etch stop layer containing aluminium and phosphorous, the top layer including first and second spaced apart recesses extending through the top layer to the etch stop layer and defining an optical waveguide therebetween. Also a method of manufacture of an optical waveguide structure including the steps of: providing a multilayer semiconductor wafer including a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer including aluminium and phosphorous; and etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.

Abstract: The use of regularly repeated small sections of pattern in making a complete optical grating may generate unwanted effects, such as side lobes, as a result of the regular repetition of defects in the small sections. Methods are described for disrupting the regularity of the occurrence of such defects in a grating made of a plurality of sections, thereby minimizing the likelihood of the occurrence of unwanted side lobes, for example.