  We report efficient generation of correlated photon pairs through degenerate
four-wave mixing in microstructure fibers. With 735.7 nm pump pulses producing
conjugate signal (688.5 nm) and idler (789.8 nm) photons in a 1.8 m
microstructure fiber, we detect photon pairs at a rate of 37.6 kHz with a
coincidence/accidental contrast of 10:1 with a full-width-at-half-maximum
bandwidth of 0.7 nm. This is the highest rate reported to date in a fiber-based
photon source. The nonclassicality of this source, as defined by the
Zou-Wang-Mandel inequality, is violated by 1100 times the uncertainty.
