Two-photon single mode coupling efficiency: definition, measurement, optimization.
Stefania Castelletto, Ivo Pietro Degiovanni, Alan L. Migdall, Micheal Ware · 2004
The authors investigate the physical meaning of coupling a two-photon field (non-classical state of light) into two single mode optical fibers, studying the limits to this due to a non-coherent emission of photons in parametric down conversion, an important starting point for many single photon source schemes