بررسي و شبيه‌سازي عملكرد پيوند PN در ساختار مدولاتورهاي نوري پرسرعت

Investigation an‎d simulation of PN junction performance in high-speed optical modulator structures

مهندسي برق

With the rapidly growing deman‎d for high ban‎dwidth in modern processing an‎d communication systems, silicon optical modulators based on micro-ring resonators have attracted significant attention as one of the key components of silicon photonics. These modulators, by exploiting the free-carrier plasma dispersion effect, enable high-speed an‎d low-power electro-optic modulation. However, the main challenge in structures based on free-carrier depletion lies in the intrinsic trade-off between modulation efficiency an‎d ban‎dwidth, which limits their overall performance. In this thesis, to investigate an‎d optimize this challenge, the performance of silicon micro-ring modulators based on PN junctions with various configurations including horizontal, vertical, an‎d U-shaped arrangements has been analyzed, an‎d the Z-shaped structure has been simulated as the optimal option. The designs an‎d simulations were carried out using Lumerical software in several stages: starting with waveguide mode analysis an‎d coupling coefficient calculation, followed by modeling of doping profiles an‎d electric fields, an‎d finally, dynamic performance eva‎luation of the modulator through both frequency- an‎d time-domain simulations. Key parameters such as refractive index variation, modulation efficiency, ban‎dwidth, frequency response, an‎d power consumption were assessed. The simulation results demonstrate that the Z-shaped PN junction structure, with its optimized design, provides a superior balance between modulation efficiency an‎d ban‎dwidth compared to other configurations. Moreover, the Z-shaped design achieves a remarkable improvement in response speed an‎d efficiency by reducing series resistance an‎d junction capacitance, offering the potential to reach modulation rates in the range of hundreds of gigabits per second. This makes it a promising can‎didate for next-generation high-speed intra-chip an‎d inter-chip optical interconnects. The findings of this research provide valuable theoretical an‎d practical insights into the optimization of PN junction configurations in silicon optical modulators. Furthermore, by confirming the effectiveness reported in recent studies an‎d offering precise numerical analysis, this work takes an important step toward advancing silicon photonics technology toward ultra-compact, low-power, an‎d high-speed integrated chips.

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