Abstract

Both the symmetric 1×2 directional coupler and the asymmetric Mach-Zehnder interferometer can function as linear modulators that are passively biased about the optimum operating point.^1,2 Their performance is comparable for ideal devices, and results near the theoretical limit have been experimentally obtained.^3,4 Our interest here is to study factors leading to nonideal behavior in order to predict device yield. To accomplish this we have (1) developed models incorporating the intrinsic phase mismatch Δβ_o between the two waveguides; (2) measured that Δβ_o distributions for both devices; and (3) experimentally demonstrated that Δβ_o impacts performance (linear dynamic range and sensitivity) as predicted by theory.

© 1990 Optical Society of America