Anisotropically Etched Deep Gratings for InP/InGaAsP Optical Devices.

We report a new grating fabrication technique suitable for optical devices in the InP/InGaAsP system. Following a holographically defined wet etch just to pattern an ultra-thin masking layer grown by chemical beam epitaxy, selective and anisotropic wet etching is shown to yield exceptionally deep high pitch gratings with reproducible profiles and dimensions.