Different geometries of electromagnetic superheterodyne amplification in nitride films

Two geometries of the superheterodyne amplification of electromagnetic pulses of the optical range are investigated theoretically in the waveguides on the base of n-GaN and n-InN films. In the first geometry the pump optical wave moves oppositely to the signal wave, in the second geometry all interacting waves move in the same direction. This amplification is the transfer of the amplification of the space charge wave due to the negative differential conductivity under the three-wave resonant interaction of two electromagnetic waves of the optical range and the space charge wave of the millimeter or terahertz range. The preferences of these geometries are pointed out.