Waveguide-integrated, ultralow-energy GeSi electro-absorption modulators

Waveguide-integrated photonic modulators are crucial devices when encoding optical signals for electronic-photonic integration on silicon. Silicon photonic modulators based on the free carrier plasma dispersion effect have undergone significant development in recent years, reaching speeds of 40Gbits-1 (ref.7). Some issues yet to be resolved include the large size and the relatively high energy consumption of silicon Mach-Zehnder interferometer modulators, and the susceptibility to fabrication errors as well as a limited operation wavelength range of 1nm for silicon microring modulators. We demonstrate the first waveguide-integrated GeSi electro-absorption modulator on silicon with a small active device area of 30νm2, a 10-dB extinction ratio at 1,540nm, an operating spectrum range of 1,539-1,553nm, ultralow energy consumption of 50fJ per bit, and a 3-dB bandwidth of 1.2GHz. This device offers unique advantages for use in high-performance electronic-photonic integration with complementary metal oxide semiconductor circuits. © 2008 Macmillan Publishers Limited. All rights reserved.