  Configurable and scalable continuous variable quantum networks for
measurement-based quantum information protocols or multipartite quantum
communication schemes can be obtained via parametric down conversion (PDC) in
non-linear waveguides. In this work, we exploit symmetric group velocity
matching (SGVM) to engineer the properties of the squeezed modes of the PDC. We
identify type II PDC in a single waveguide as the best suited process, since
multiple modes with non-negligible amount of squeezing can be obtained. We
explore, for the first time, the waveguide dimensions, usually only set to
ensure single-mode guiding, as an additional design parameter ensuring
indistinguishability of the signal and idler fields. We investigate here
potassium titanyl phosphate (KTP), which offers SGVM at telecommunications
wavelengths, but our approach can be applied to any non-linear material and
pump wavelength. This work paves the way towards the engineering of future
large-scale quantum networks in the continuous variable regime.
