Intermodal coupling in an optical fiber using periodic stress.
Few-mode optical fibers have many potential uses in information and sensor applications, but their effectiveness depends on being able to couple efficiently and selectively into and out of the different modes. Coherent coupling between the first- and second-order modes of a bimodal optical fiber can be achieved by periodically stressing the fiber once per beat length. An analysis of such a device is presented, and it is shown that the device is broadband and polarization sensitive and can have a coupling efficiency of 96% with an insertion loss of only a few percent. We compare our theoretical results to experimental data.
Garth
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