In support of our work in quantum technologies including secure optical communications, we are undertaking an extensive study of some of the fundamental aspects of quantum photonics. Topics currently under investigation include the development of laboratory measures to quantify the degree of entanglement between two optical fields and their mutual information content, the use of entanglement witnesses to perform such studies in an efficient manner, the use of quantum tomography to characterize quantum states, and techniques for the direct measurement of the quantum wavefunction. We are also very interested in developing methods for improved metrology based on the use of entangled photons and other quantum states of light.