Study of Ring-Assisted Mach-Zehnder Interferometer Modulators

A microring-assisted Mach-Zehnder interferometer has been studied. The structure demonstrates better extinction ratio, eye opening and bandwidth than a single microring modulator. The extinction of the ring-assisted Mach-Zehnder interferometer can be further tailored by controlling the amount of light coupled to each of the interferometer arms. A 7 dB improvement in the extinction ratio over that of a standalone micro-ring device is observed for a 7.54 µm ring radius when operated in over-coupled regime at around 1310 nm wavelength.