  We verified operational approach based on direct measurement of entanglement
degree for bipartite systems. In particular spectral distributions of single
counts and coincidence for pure biphoton states generated by train of short
pump pulses have been measured and entanglement quantifier calculated. The
approach gives upper bound of entanglement stored in total biphoton states,
which can reach extremely high value up to $10^{4}-10^{5}$.
