2013/04/04 by Younghyun Kim, Mitsuru Takenaka, Kim, Younghyun +7
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices #Silicon Nanostructures and Photoluminescence #physics.optics
paper · pdf · doi:10.48550/arxiv.1304.1229
arxiv created 2013/04/04 · openalex publication_date 2013/04/04 · arxiv updated 2013/04/05 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
The plasma dispersion effect and free-carrier absorption are widely used for changing refractive index and absorption coefficient in Si-based optical modulators. However, these free-carrier effects in Si are not large enough for making the footprint of the Si modulators small. Here, we have theoretically and experimentally investigated the enhancement of the plasma dispersion effect and free-carrier absorption by strain-induced mass modulation in silicon-germanium (SiGe). The application of compressive strain to SiGe reduces the conductivity hole mass, resulting in the enhanced free-carrier effects. Thus, the strained SiGe-based optical modulator exhibits more than twice modulation efficiency as large as that of the Si modulator. To the best of our knowledge, it is the first demonstration of the enhanced free-carrier effects in strained SiGe at the near-infrared telecommunication wavelength. The strain-induced enhancement technology for the free-carrier effects is expected to boost the modulation efficiency of the most Si-based optical modulators thanks to high complementary metal-oxide-semiconductor (CMOS) compatibility.