Configurable spatio-temporal properties in a photon-pair source based on   spontaneous four wave mixing with multiple transverse modes
  We present an experimental and theoretical study of photon pairs generated by spontaneous four wave mixing (SFWM), based on birefringent phasematching, in a fiber which supports more than one transverse mode. We present SFWM spectra, obtained through single-channel and coincidence photon counting, which exhibit multiple peaks shown here to be the result of multiple SFWM processes associated with different combinations of transverse modes for the pump, signal, and idler waves. 
Daniel Cruz-Delgado, Jorge Monroy-Ruz Angela M. Barragan, Erasto   Ortiz-Ricardo, Hector Cruz-Ramirez, Roberto Ramirez-Alarc...
quant-ph physics.optics