Mode conversion under the influence of ultrashort laser pulses in planar semiconductor waveguides

An experimental study was made of the processes of intermode conversion of surface light waves in semiconductor waveguides in which diffraction gratings were induced by ultrashort (~ 20 ps) light pulses. The conversion efficiency was determined as a function of the power density of ultrashort pulses and of the delay time between the moments of excitation and probing of the diffraction grating. The efficiency of conversion of ultrashort pulses from the TE₀ to the TE₁ mode was 65%. The magnitude of the efficiency and its kinetics depended strongly on the processes of the induced absorption of light.