Micro-Nano Electro-Optic Modulator Structure Based on the Si/SiGe/Si Material

The modulation power consumption and the modulation efficiency are the key parameters of the electro-optic modulator, which directly affect the electro-optic modulator's photoelectric properties. Improving the performance of the electro-optic modulator, a micro-nano electro-optic modulator structure based on the Si/SiGe/Si material is proposed in this paper, which has low power consumption and high efficiency. After the plasma dispersion effects and the thermo-optic effects are analyzed, we can know that the performance of the electro-optic modulator could be affected by the carrier concentration and the temperature of modulator. Silicon Germanium (SiGe) material is attached to the common Silicon (Si) electro-optic modulator, and a large injection ratio is obtained from the Si/SiGe/Si double hetero-junction. With the modulation region's carrier concentration rise, and the working voltage and the power consumption of modulator all are reduced. The jugged active region structure is attached to the common Si electro-optic modulator, and the probability of inelastic collision among carriers is decreased, so the temperature rise of modulator can be reduced. The thermal-optic effects are weakened, and the modulation efficiency is increased. The simulation results show that the working voltage of the jugged SiGe modulator is less than that of the Silicon modulator at the same refractive index differences, and the jugged SiGe modulator has lower modulation power consumption; the jugged SiGe modulator's effective refractive index differences are more than the Silicon modulator's effective refractive index differences at the same working voltage, and the jugged SiGe modulator has higher modulation efficiency. Therefore, this jugged SiGe modulator is a micro-nano electro-optic modulator with lower power consumption and higher efficiency.

A Sigma-Delta Modulator System Design with 2-2 Mash Structure

Σ-Δ modulator structure is increasingly becoming complex, it is very necessary to improve the design efficiency by the level of behavior model in the simulation. The paper discussed several important Σ-Δ modulators with ideal factors, and gives corresponding behavior model. Then, the paper shows a behavior level design with non-ideal factors. Under the condition that sample rate is 256 and input signal frequency is 250 KHz, the SNR can get 105 dB, the effective bit can get 16 bit. It can be used in audio and electronic equipment.