  A quantitative analysis is conducted on the impacts of experimental
imperfections in the input state, the detector properties, and their
interactions on photon-subtracted squeezed vacuum states in terms of a quantum
non-Gaussian character witness and Wigner function. Limitations of the
non-classicality and quantum non-Gaussian characteristic of Schr\"{o}dinger
kitten states are identified and addressed. The detrimental effects of a
photon-number detector on the generation of odd Schr\"{o}dinger kitten state at
near-infrared wavelengths ($\sim$ 860 nm) and telecommunication wavelengths
($\sim$ 1550 nm) are presented and analysed. This analysis demonstrates that
the high dark count probability of telecommunication-wavelength photon-number
detectors significantly undermines the negativity of the Wigner function in
Schr\"{o}dinger kitten state generation experiments. For a
one-photon-subtracted squeezed vacuum state at $\sim$ 1550 nm, an APD-based
photon-number-resolving detector provides no significant advantage over a
non-photon-number-resolving detector when imperfections, such as dark count
probability and inefficiency, are taken into account.
