The efficiency of an electro-optic (EO) directional coupler (DC) and a Mach–Zehnder (MZ) switch is discussed. The specific designs employ a passive waveguide core and an EO cladding. The performance of a DC switch was evaluated by numerical methods, namely coupled mode theory (CMT), eigenmode expansion (EME) method, and beam envelope method. Using the CMT and EME methods, it is shown that in the DC with a passive waveguide core and EO cladding at certain waveguide parameters the switching effect does not take place. The effect is demonstrated for the first time and suggests that careful optimization of the DC switch should be done before experimental realization of the device. The efficiency of an optimized DC switch is shown to be of an order lower than that of an MZ switch.
"Evaluation of performance of a hybrid electro-optic directional coupler and a Mach–Zehnder switch," Journal of Nanophotonics 11(1), 016013 (9 March 2017). https://doi.org/10.1117/1.JNP.11.016013
. Submission: Received: 14 November 2016; Accepted: 21 February 2017
Received: 14 November 2016; Accepted: 21 February 2017; Published: 9 March 2017