  Many quantum computation and communication schemes require, or would
significantly benefit from, true sources of single photon on-demand (SPOD).
Unfortunately, such sources do not exist. It is becoming increasingly clear
that coupling photons out of a SPOD source will be a limiting factor in many
SPOD implementations. In particular, coupling these source outputs into optical
fibers (usually single mode fibers) is often the preferred method for handling
this light. We investigate the practical limits to this coupling as relates to
parametric downconversion, an important starting point for many SPOD schemes.
We also explored whether it is possible to optimize the engineering of the
downconversion sources to improve on this coupling. We present our latest
results in this area.
