  Recently, low light level charge coupled devices (L3CCDs) capable of on-chip
gain have been developed, leading to sub-electron effective readout noise,
allowing for the detection of single photon events. Optical interferometry
usually requires the detection of faint signals at high speed and so L3CCDs are
an obvious choice for these applications. Here we analyse the effect that using
an L3CCD has on visibility parameter estimation (amplitude and triple product
phase), including situations where the L3CCD raw output is processed in an
attempt to reduce the effect of stochastic multiplication noise introduced by
the on-chip gain process. We establish that under most conditions, fringe
parameters are estimated accurately, whilst at low light levels, a bias
correction which we determine here, may need to be applied to the estimate of
fringe visibility amplitude. These results show that L3CCDs are potentially
excellent detectors for astronomical interferometry at optical wavelengths.
