Optical Fiber Telecommunications VA, 5th Edition

have plotted the coincidence rate as a function of the geometric mean of the signal

and idler count rates; in fact, because the efficiency of the two detectors is

different, we measure different single-photon count rates in the two channels.

Dark counts have been subtracted from the plotted count rates. For the coincidence

rates, both dark–dark and photon–dark coincidences have to be taken in account,

but for the counting rates in our experiment the former are negligible. Thus far,

we have achieved a maximum coincidence rate of 10

3

counts/s (= coincidence

rate/pulse gate-pulse rate), which is expected to go up by at least a factor of

10 with use of a higher repetition-rate gate-pulse generator.

We have performed two independent experiments to demonstrate ...