  The purpose of this paper is to show how a class of classical linear
stochastic systems can be physically implemented using quantum optical
components. Quantum optical systems typically have much higher bandwidth than
electronic devices, meaning faster response and processing times, and hence has
the potential for providing better performance than classical systems. A
procedure is provided for constructing the quantum optical realization. The
paper also describes the use of the quantum optical realization in a
measurement feedback loop. Some examples are given to illustrate the
application of the main results.
