The idler photon is fibre-coupled and sent to a second SPDC crystal, a 30 mm Type-I phase matched PPLN waveguide (HC Photonics), where it splits into a pair of granddaughter photons at 1570 and 1530 nm.
The idler photon is fibre-coupled and sent to a second SPDC crystal, a 30 mm Type-I phase matched PPLN waveguide (HC Photonics), where it splits into a pair of granddaughter photons at 1570 and 1530 nm.