Abstract:

We propose to use SiO₂ gratings on the InP membrane on silicon (IMOS) platform to form ultra-weak gratings antennas for generation of ultra-narrow free-space optical beams. Such long gratings can produce narrow beam widths of below 0.1 degree. By using selective dry etching, both the grating shape and the etch depth can be precisely controlled, yielding a highly robust fabrication process. Initial results have shown a 0.088° FWHM of the emitted beam in the far-field for a 1-mm antenna length.