10 MHz single photon counting at 1.3 micron.

We have demonstrated single photon detection (for lambda=1. 3 micron) at a counting rate of 10 MHz. This is the highest photon counting rate ever achieved. We find that the quantum efficiency eta is a weak function the dark count rate of r (d), namely eta(proportional)(r(d))(0.2). These results are encouraging for possible quantum limited lightwave receiver applications.