Investigation of Resonantly Enhanced Modulators on<tex>$hboxLiNbO_3$</tex>Using FEM and Numerical Optimization Technique

Systematic design approach for optimized resonantly enhanced Mach-zehnder Modulators

“…An overlap between the guided optical mode calculated using a finite difference modeling (FDM) [19] and the static electric field in the active region, along with the electrooptic coefficient, can be used to calculate the relationship between optical phase shift and applied electric potential. The placement of the RF electrode on the optical waveguides is essential to find the optimum efficiency represented by V π as reported in [20] and given by (1). Thus, the computed induced phase shift is a function of the optimum placement of the RF electrode, the electrode characteristics, and the optical waveguide characteristics.…”

“…In this section, we use the model in Section II to synthesize an optimized RE-MZM device [5], [20]. This RE-MZM has been fabricated and characterized, and the numerical model is validated through comparison with measurements.…”

“…10(a). The RE-MZM uses an unenhanced modulator, however, the input and output ports are terminated with discontinuities as proposed in [5] and [20]. These discontinuities are the shorted-stub CPW structures as shown in Fig.…”

“…At the input and output ports, two-port and one-port shorted-stub structures are used. These structures were optimized using the numerical model for the corresponding traveling-wave electrode of the modulator as reported in [20] at an operational frequency of 1.8 GHz. The numerical tool in Section II provided the various transmission line characteristics of the optimized RE-MZM device.…”

“…Having obtained the optimal configuration as described in [20], it was possible to fabricate and characterize each of the transmission line components identified in Fig. 10(b).…”