Highly Efficient Silicon Michelson Interferometer Modulators

We present the first high-speed silicon Michelson interferometer (MI) modulator with two 500 μm-long phase shifters. The utilized MI optical structure is an enhanced Mach-Zehnder interferometer (MZI) with both arms incorporated with reflective mirrors. The light in the MI travels back and forth along the phase shifting waveguides and therefore doubles the effective length of light-carrier interaction. Improvement on the modulation efficiency is experimentally demonstrated. Our MI modulator shows high efficiency with a low figure of merit V_πL_π of 0.72 V·cm~0.91V·cm under the bias of -1 V~-6V. High-speed modulations are performed at 25 Gbit/s and 30 Gbit/s with the extinction ratio of 8 dB and 6.5 dB, respectively, showing great potential in the future optical interconnects.