Investigation of a low-voltage polymeric 2 × 2 Mach-Zehnder interferometer optical switch using five-serial-coupled electro-optic microrings

Structure and design scheme of a Mach-Zehnder interferometer (MZI) EO switch, whose one arm is assisted by five serial-coupled microrings, is proposed and optimized. Using the derived formulas and expressions of output power, insertion loss and crosstalk, detailed design and optimization are performed. Under 1550-nm wavelength, analysis results indicate that the device can perform normal switching function and the low switching voltage is as low as 0.99 V. The insertion loss is 1.15 dB at bar state, whereas that is 1.97 dB at cross state; the crosstalk is −17.8 dB at bar state, whereas that is −12.3 dB at cross state. The voltage-length product of the proposed switching device is about 0.21 V·mm, which is 32 times smaller than that of the traditional MZI EO switch (6.69 V·mm) with the same waveguide and electrode parameters. Therefore, due to small footprint size and extremely low switching voltage, this switching configuration can be densely integrated onto optoelectronic chips.