Silicon photonics, one of the most promising candidates for breaking the bottleneck of current optical transmission systems, has been developing rapidly in both performance and maturity. The analysis and design of the two key components of this technology, the optical modulator and detector, are presented in this paper. The Mach⁃Zehnder modulator with U⁃type PN junction is optimized to obtain the modulation efficiency of 0.559 V·cm. The electro⁃optical 3 dB bandwidth of this device is 30 GHz. The simulation of the PIN waveguide Si based Ge photodetector at 1.55 μm wavelength is also presented. The device shows a very low dark current of about 10 nA at ⁃1 V, and the obtained responsivity and 3 dB bandwidth are appreciable. These results practically meet the requirement of commercial 100 Gb/s optical transmission systems.
silicon photonics; modulator; detector