We compute the output of multimode cavity-enhanced spontaneous parametric down-conversion (SPDC) for sub-threshold, but otherwise arbitrary, gain. We find analytic Bogoliubov transformations that allow us to calculate arbitrary field correlation functions, including the second-order intensity correlation function G(2)(T). The results show evidence of increased coherence due to stimulated SPDC. We extend an earlier model [Lu and Ou, Phys. Rev. A, 62, 033804 (2000)] to arbitrary gain and finesse, and show the extension gives accurate results in most scenarios. The results will allow simple, analytic description of cavity-based nonclassical light sources for quantum networking, quantum-enhanced sensing of atoms and generation of highly non-classical field states
@article{arxiv.1409.1117,
title = {Theory of high gain cavity-enhanced spontaneous parametric down-conversion},
author = {Joanna A. Zielińska and Morgan W. Mitchell},
journal= {arXiv preprint arXiv:1409.1117},
year = {2015}
}