Unbalanced versus balanced operation in an optical coherence tomography system

The choice of a balanced optical coherence tomography (OCT) configuration versus an unbalanced OCT configuration with optimized reference-arm attenuation is discussed. The choice depends on the receiver noise, the fiber-end reflection R, and the power to the object. When OCT is used to investigate biological tissue an equivalent R′ can be evaluated as the compound reflected light from tissue. In this case an additional parameter has to be considered: the confocal optical sectioning interval of the OCT system.