  A semiclassical model is presented for characterizing the linear response of
elementary quantum optical systems involving cavities, optical fibers, and
atoms. Formulating the transmission and reflection spectra using a
scattering-wave (transfer matrix) approach, the calculations become easily
scalable. To demonstrate how useful this method is, we consider the example of
a simple quantum network, i.e., two cavity-QED systems connected via an optical
fiber. Differences between our quasi-exact transfer matrix approach and a
single-mode, linearized quantum-optical model are demonstrated for parameters
relevant to recent experiments with coupled nanofiber-cavity-QED systems.
