A concept for calculation of element parameters and analyzing the output power in the fiberoptic interferometric schemes with time-division multiplexing of the sensitive elements (TDM) has been put forward in the paper. The calculation procedure of element parameters allows ensuring the equality of the optical power from all multiplexed sensitive elements, as well as evaluating the effect of deviation of the optical scheme parameters from the calculated ones. Using two optical schemes as an example, the implementation of this calculation concept, the sequence of obtaining mathematical expressions, and examples of calculation results were presented. The proposed calculation method could be successfully applied in the design of interferometric meters with multiplexing of fiber-optic sensitive elements.