We theoretically investigate the photon statistics in a cavity quantum electrodynamics system of a single quantum dot
(QD) coupled to photonic molecule. Our previous work [Wen Zhang et.al, Phys. Rev. A 89, 043832 (2014)] has shown
that QD-bimodal cavity system can generate ultrastrongly sub-Poissonian light by regulating the ratio between driving
strengths of two cavity modes. Here we study two coupled single-mode nanocavities with a QD coupling to one of them
as a photonic molecule system. Statistical character of photon emission is presented by evaluating the zero-delay secondorder
correlation function g2(0). When both cavities with/without QD are driven, the sub-Poissonian character can be
optimized by regulating the ratio between driving strengths of each cavities. We also present the dependences of other
system parameters on the photon statistics. The physical mechanism of both effects is to optimize the combination of
super-Poissonian and coherent light which results in sub-Poissonian light generation. As a result g2(0) can be reduced up
to several orders of magnitude compared with the QD coupled one-mode-cavity system.
We theoretically investigate the sub-Poissonian light generation in a cavity quantum electrodynamics system of a single
quantum dot coupled a bimodal nanocavity. It is shown in a recent work [Arka Majumdar et.al, Phys. Rev. Lett. 108,
183601 (2012)] that the system can generate strongly sub-Poissonian light when one of the cavity modes is driven
coherently and resonantly. We study the two-mode coherent driving regime of the coupled system. The effect of additional
cavity mode driving on the statistic characteristics of photon emission is presented by evaluating the zero-delay
second-order correlation function g2(0). We interpret the optimization of sub-Poissonian feature by regulating the ratio between driving strengths of two cavity modes and observe that g2(0) can be reduced up to several orders of magnitude (g2(0))<10-4), comparing with one-mode driving system (g2(0)~0.1), indicating ultra-strongly sub-Poissonian light generation.