150$ mm), PPKTP nonlinear crystal for SPDC. Manipulation: BD beam dump, SLM spatial light modulator, symmetric two lens (L1, L2) imaging arrangement ($f = 100$ mm) to magnify the spectral resolution by 1:6, four-prism compressor. Detection: PPKTP nonlinear crystal for SFG, BF bandpass filter, SPCM single photon counting module with a two lens (L3, L4) imaging system.](setup_extended_L.eps){width="100.00000%"}

Energy-time entangled photons are created by SPDC in a periodically poled KTiOPO$_4$ (PPKTP) crystal with length $L_{DC}=11.5$ mm and a poling periodicity of $G_{DC}=9$ $\mu$m. The pump is a single mode 5 W Nd:YVO$_{4}$ (Coherent Verdi V5) laser operating at 532 nm with a spectral bandwidth of about $\Delta \nu_p=5$ MHz. According to type-0 phase matching, the created idler and signal photons have the same polarization as the pump photon. The operating temperature of the PPKTP crystal is optimized for almost degenerate and collinear emission with a spectral width of the down-converted photons of $\Delta \lambda_{DC}\approx 105$ nm centered around 1064 nm.

To control the SPDC spectrum, it is dispersed in a symmetric four-prism compressor consisting of equilateral N-SF11 prisms in minimum deviation geometry. At the same time, the prism compressor serves to compensate for the total accumulated group velocity dispersion in the 