Numerical simulation of a silicon-on-insulator waveguide structure for phase modulation at 1.3 μm

This paper presents an analysis of a silicon-on-insulator (SOI) waveguide structure to be used for phase modulation at 13 mu m. The device consists of a two-dimensional (2-D) strip waveguide and a P+/N-/N+ lateral diode to realize the effective index modulation by free-carrier injection. We have calculated that an effective index modulation between 5.10(-4) and 10(-3) could be obtained with current densities in the range from 500 to 1600 A/cm(2). A detailed numerical simulation of the device transient response is also reported, We demonstrate that an effective index modulation of 5.10(-4) could be obtained with a cutoff frequency of about 100 MHz. The phase modulator has a predicted figure-of-merit (FoM) of 160 degrees/V/mm and a chirp factor of 25. Due to its full compatibility with complementary metal-oxide-semiconductor (CMOS)-SOI technology, the device is interesting for low-cost silicon-based optoelectronic systems.