Simulation and analysis of a high-efficiency silicon optoelectronic modulator based on a Bragg mirror

We describe the operating principle of a silicon optoelectronic modulator b ased on the plasma dispersion effect used in conjunction with a distributed Bragg reflector, which converts the phase shift, induced by the free carri ers injected by a P-i-N diode, into variations of its reflectivity. The dev ice is integrated in a low-loss silicon-on-insulator waveguide. Two differe nt approaches in the driving schemes are proposed. Moreover, we show how it is possible to reach a theoretical 100% modulation depth by exploiting in a concurrent way both the variations of the refractive index and the increa sed optical absorption. An exhaustive description of the optical structure and its guiding properties, together with the analysis of the electrical be havior of the modulator, is given. Finally, a comparison with other interfe rometric structures is analyzed, and it is shown how this kind of modulator exhibits satisfactory characteristics in terms of dissipated power and red uced occupation of area on a chip. (C) 2001 Society of Photo-Optical Instru mentation Engineers.