A compact source of polarization-entangled photon pairs at a wavelength of
856 nm is realized using a frequency-doubled laser diode as the pump source
for cavity-enhanced type-II spontaneous parametric down-conversion. Our se
tup generates photon pairs with entanglement visibility of greater than or
equal to 95% and with count rates comparable to those of standard experimen
ts based on large-frame ion lasers. (C) 2001 American Institute of Physics.