Variable optical buffer using slow light in semiconductor nanostructures

A compact variable all-optical buffer using semiconductor quantum dot (QD) structures is proposed and analyzed. The buffering effect is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium via electromagnetically induced transparency effect. We present a theoretical investigation of the criteria for achieving slow light in semiconductor QDs. A QD structure with presence of strain is analyzed with the inclusion of the polarization-dependent intersubband dipole selection rules. Experimental methods to synthesize and the measurements of coherent properties in state-of-the-art QDs are surveyed. Slow-light effects in uniform and nonuniform QDs are compared. Finally, optical signal propagation through the semiconductor optical buffer is presented to demonstrate the feasibility for practical applications.