Abstract:
We show that Mach-Zehnder interferometers (MZIs) formed
from waveguides in a perfectly reflecting cladding can display manifestly
different transmission characteristics to conventional MZIs due to mode
recirculation and resonant reflection. Understanding and exploiting this
behavior, rather than avoiding it, may lead to improved performance of
photonic crystal (PC) based MZIs, for which cladding radiation is forbidden
for frequencies within a photonic bandgap. Mode recirculation in such
devices can result in a significantly sharper switching response than in
conventional interferometers. A simple and accurate analytic model is
presented and we propose specific PC structures with both high and low
refractive index backgrounds that display these properties.
