Broadband wavelength plate device based on optical phase modulation and manufacturing method therefor

A method of fabrication a broadband waveplate device, the method comprising:

• forming, on a substrate, a multiple-quantum-well layer in which well layers and barrier layers are alternately stacked;
• forming a first conductive layer on the multiple-quantum-well layer;
• removing the substrate;
• forming a temporary conductive layer on a surface of the multiple-quantum-well layer in a direction away from the first conductive layer;
• forming a sacrificial layer on the temporary conductive layer;
• forming, in the sacrificial layer, a plurality of openings parallel to one another;
• forming an antenna layer having a shape of a plurality of stripes parallel to one another, by removing portions of the temporary conductive layer exposed through the plurality of openings of the sacrificial layer;
• and
• removing the sacrificial layer.