Integrated multimode interference coupler-based mach-zehnder interferometric modulator fabricated on a silicon-on-insulator substrate

The authors propose the design of a 6000×40-μm Mach-Zehnder interferometric (MZI) electro-optic modulator fabricated on silicon-on-insulator (SOI) substrate based on a back-to-back cascade of two 1×2 multimode interference (MMI) couplers for the operating wavelength of 1.55μm. A signal modulation is achieved with the incorporation of a phase shifter in one of the two arms that connect two MMI devices together and the resultant extinction ratio achieved is in the excess of -25dB. Furthermore, the frequency response measurement also shows that the 3-dB frequency measured for our MMI-MZI device is greater than 6 MHz.