  A new engineering technique using continuous quantum measurement in
conjunction with feed-forward is proposed to improve indistinguishability of a
single-photon source. The technique involves continuous monitoring of the state
of the emitter, processing the noisy output signal with a simple linear
estimation algorithm, and feed forward to control a variable delay at the
output. In the weak coupling regime, the information gained by monitoring the
state of the emitter is used to reduce the time uncertainty inherent in photon
emission from the source, which improves the indistinguishability of the
emitted photons.
