  The momentum dependence of the low energy quasiparticle spectrum and the
related Bogoliubov angle in cuprate superconductors are studied within the
kinetic energy driven superconducting mechanism. By calculation of the ratio of
the low energy quasiparticle spectra at positive and negative energies, it is
shown that the Bogoliubov angle increase monotonically across the Fermi
crossing point. The results also show that the superconducting coherence of the
low energy quasiparticle peak is well described by a simple d-wave
Bardeen-Cooper-Schrieffer formalism, although the pairing mechanism is driven
by the kinetic energy by exchanging spin excitations.
