Stability Problems of High Frequency Signals Generated by Direct Mixing Two Laser Beams

Abstract

In this paper we study the radio frequency (RF) signal properties generated by direct mixing two laser beams, which can be used in very high frequency (e.g. terahertz) communications. We show the supply source stability has a critical effect in this procedure. It can broaden the RF signal spectrum up to 1 GHz. Although the linewidth of the lasers is the main factor determining the spectral width of the generated RF signal, the supply source instability also has a very significant contribution. In this paper we show the effect of these parameters by simulations and measurements.