  A significant problem for optical quantum computing is inefficient, or
inaccurate photo-detectors. It is possible to use CNOT gates to improve a
detector by making a large cat state then measuring every qubit in that state.
In this paper we develop a code that compares five different schemes for making
multiple measurements, some of which are capable of detecting loss and some of
which are not. We explore how each of these schemes performs in the presence of
different errors, and derive a formula to find at what probability of qubit
loss is it worth detecting loss, and at what probability does this just lead to
further errors than the loss introduces.
