Coherence multiplexing using a parallel array of electrooptic modulators and multimode semiconductor lasers

The paper presents a rather new approach of electrooptic modulation of light suitable for coherence multiplexing
N
transmission channels. A parallel array of
N
electrooptic multiplexers powered by multimode semiconductor lasers is used for imprinting the signals on light simultaneously. It is shown that the electrooptic multiplexers have to generate optical time delays whose optimal values are ruled by the sequence
1/2N \cdot \delta f, 1/N \cdot \delta f, 3/2N \cdot \delta f
, etc., where
\delta f
is the intermodal separation of the laser longitudinal modes. The performance of the system is discussed in terms of crosstalk, number of possible channels, and signal power. The demonstration of the method is reported in the area of optical communications with the transmission of base-band video signals.