  Free-space optical (FSO) links are considered as a cost-efficient way to fill
the backhaul/fronthaul connectivity gap between millimeter wave (mmWave) access
networks and optical fiber based central networks. In this paper, we
investigate the end-to-end performance of dual-hop mixed FSO/mmWave systems to
address this combined use. The FSO link is modeled as a Gamma-Gamma fading
channel using both heterodyne detection and indirect modulation/direct
detection with pointing error impairments, while the mmWave link experiences
the fluctuating two-ray fading. Under the assumption of both
amplify-and-forward and decode-and-forward relaying, we derive novel
closed-form expressions for the outage probability, average bit error
probability (BER), ergodic capacity, effective capacity in terms of bivariate
Fox's $H$-functions. Additionally, we discuss the diversity gain and provide
other important engineering insights based on the high signal-to-noise-ratio
analysis of the outage probability and the average BER. Finally, all our
analytical results are verified using Monte Carlo simulations.
