Metrological characterization of fiber optic QKD components towards proofing the implementation security of QKD. The facilities existing and under build-up comprise: 1. Optical transmission of fiber optic components between 1490 nm and 1630 nm 2. Assessing multi-photon emission characteristics via measuring higher-order correlation coefficients up to g(4) 3. Hong-Ou Mandel interferometry and quantum state tomography of entangled photon pair sources 4. CV QKD testbench including assessment of source laser RIN, phase noise and wavelength stability