  Optical coherence tomography has become an important imaging technology in
cardiology and ophthalmology, with other applications under investigations.
Major advances in optical coherence tomography (OCT) imaging are likely to
occur through a quantum field approach to the technology. In this paper, which
is the first part in a series on the topic, the quantum basis of OCT first
order correlations is expressed in terms of full field quantization.
Specifically first order correlations are treated as the linear sum of single
photon interferences along indistinguishable paths. Photons and the
electromagnetic (EM) field are described in terms of quantum harmonic
oscillators. While the author feels the study of quantum second order
correlations will lead to greater paradigm shifts in the field, addressed in
part II, advances from the study of quantum first order correlations are given.
In particular, ranging errors are discussed (with remedies) from vacuum
fluctuations through the detector port, photon counting errors, and position
probability amplitude uncertainty. In addition, the principles of quantum field
theory and first order correlations are needed for studying second order
correlations in part II.
