Effect of hole pile-up at heterointerface on modulation voltage in GaInAsP electroabsorption modulators

Abstract

Input optical power dependence of the modulation voltage for GaInAsP electroabsorption modulators is studied. It is shown that the photogenerated hole pile-up at a heterointerface induces the increase of modulation voltage for the same extinction ratio with increasing the input optical power. The effect of the hole pile-up was greatly reduced in the new structure with the buffer layer of intermediate bandgap between the GaInAsP waveguide and InP upper clad layers.