Linewidth tolerance for THz communication systems using phase estimation algorithm

This paper presents the impact of signal linewidth on photonic THz wireless systems using phase estimation (PE) algorithms at the receiver. The penalty associated with signal linewidth, as well as the optical linewidth requirements for systems using free-running lasers are evaluated using extensive Monte Carlo simulations for different modulation formats. The BER performance and power penalty induced by signal linewidth are also measured experimentally by varying the linewidth of the local oscillator laser. Simulation and experimental results show similar penalty trends. Differences between them are likely to be due to impairments not considered in the simulations and the THz signal linewidth being bigger than the sum of the optical linewidths of the two free-running lasers used in the experiment.