Compact integrated Si ring-resonator modulator reaches 50 Gbit/s

Ultra-high-speed data interconnection is best done optically; much research is going into boosting data rates for such devices into the tens of gigahertz. Integrated silicon (Si) waveguide-based modulators are at the heart of this research. Researchers at the Photonics Electronics Technology Research Association (PETRA; Tsukuba, Japan), the National Institute of Advanced Industrial Science and Technology (AIST; Tokyo, Japan), and the Institute for Photonics-Electronics Convergence System Technology (PECST; Onogawa, Japan) have created a 50 Gbit/s ring-resonator-based modulator that has a low drive voltage and optical insertion loss of 1.96 V and 5.2 dB, respectively. The resonator is much smaller than previous 50 Gbit/s Si-based modulators, which were too big to fit on a practical optical interconnect.

The ring is a rounded oblong 21 μm long and 9 μm wide, with a waveguide height and width of 450 and 220 nm. The ring contains two 15-μm-long voltage-controlled, p-i-n-diode-based phase shifters, each consisting of a sidewall-grating waveguide. Various input wavelengths very close to 1548 nm were used in the experiment; the modulation signal was a pseudo-random binary sequence of 27^-1. An eye diagram shows a dynamic extinction ratio at 50 Gbit/s of 4.58 dB. Contact Takeshi Baba at [email protected].