 The study derives expressions for frequency correlation and exit probability of photons generated via spontaneous parametric down-conversion, SPDC, in non-linear waveguides with linear scattering loss, which is included within a general Hamiltonian formalism by connecting waveguide modes to reservoir modes with a phenomenological coupling Hamiltonian. In the limit of low SPDC pair production probability, the presence of loss requires that the usual lossless generated pair state be written as a reduced density operator, composed of 2-photon, 1-photon, and 0-photon contributions. The bifurton probability density or joint spectral intensity, JSI, associated with the 2-photon contribution is determined by both phase matching and loss matching terms, leading to three qualitatively different regimes of SPDC JSIs depending on the relative sizes of pump and generated photon loss coefficients and frequency dependence of generated photon loss. This article was authored by L. G. Helt, M. J. Steele, and J. E. Seype. We are article.tv, links in the description below.