AN ANALYSIS OF THE PERFORMANCE OF FRANZ-KELDYSH ELECTROABSORPTION WAVE-GUIDE MODULATORS

We present an analysis of the performance limits of the Fran-Keldysh e ffect (FKE) waveguide modulators, based on the optimization of the mat erial figures of merit related to device performance. This leads to a unique design approach in which the detuning energy and the thickness of the active material determine the required drive voltage and the av ailable bandwidth, A large-core waveguide is used to minimize insertio n loss. The overall performance is compared with a similar waveguide m odulator based on the quantum confined Stark effect (QCSE). The conclu sion is that, because of the relatively small ha available from Franz- Keldysh effect, the power-bandwidth ratio of the optimized FKE modulat or is about an order of magnitude poorer than the optimized QCSE modul ator.