Experimental violation of a d-dimensional Bell inequality using   energy-time entangled photons
  We experimentally study the violation of the CGLMP inequality for entangled 2-qubit and 2-qutrit states with different degrees of entanglement using numerically optimized measurement settings. The qudits are encoded and manipulated in the frequency spectrum of broadband energy-time entangled photons by taking into account a spatial light modulator. The latter allows to discretize the spectrum into bins. By controlling each frequency bin individually, the generation of maximally and non-maximally entangled qutrits is verified through quantum state tomography. 
Sacha Schwarz, B\"anz Bessire, Andr\'e Stefanov
quant-ph