Optimal interferometer designs for optical coherence tomography

We introduce a family of power-conserving fiber-optic interferometer design s for low-coherence reflectometry that use optical circulators, unbalanced couplers, and (or) balanced heterodyne detection. Simple design equations f or optimization of the signal-to-noise ratio of the interferometers are exp ressed in terms of relevant signal and noise sources and measurable system parameters. We use the equations to evaluate the expected performance of th e new configurations compared with that of the standard Michelson interfero meter that is commonly used in optical coherence tomography (OCT) systems. The analysis indicates that improved sensitivity is expected for all the ne w interferometer designs, compared with the sensitivity of the standard OCT interferometer, under high-speed imaging conditions. (C) 1999 Optical Soci ety of America.