High contrast 40Gbit/s optical modulation in silicon

Abstract

Data interconnects are on the verge of a revolution. Electrical links are increasingly being pushed to their limits with the ever increasing demand for bandwidth. Data transmission in the optical domain is a leading candidate to satisfy this need. The optical modulator is key to most applications and increasing the data rate at which it operates is important for reducing power consumption, increasing channel bandwidth limitations and improving the efficiency of infrastructure usage. In this work silicon based devices of lengths 3.5mm and 1mm operating at 40Gbit/s are demonstrated with extinction ratios of up to 10dB and 3.5dB respectively. The efficiency and optical loss of the phase shifter is 2.7V.cm and 4dB/mm (or 4.5dB/mm including waveguide loss) respectively. ©2011 Optical Society of America

High-Speed, Low Drive-Voltage Silicon-Organic Hybrid Modulator Based on a Binary-Chromophore Electro-Optic Material

“…Note that, in contrast to earlier demonstrations of 40 Gbit/s modulation in SOH devices [11], [14], we did not use a gate voltage to improve the silicon conductivity. Still, a small voltagelength product of 1 Vmm is found for operation at 40 Gbit/s, one order of magnitude below typical values reported for reversebiased pn-modulators [1], [5]. It should be noted that a slightly better 40 Gbit/s performance was reported in our previous work [38], where the initially small EO bandwidth of the device was increased from 10 to 25 GHz by applying a gate voltage between transmission line and silicon substrate.…”

“…icon, current modulators mostly rely on the plasma-effect, using either free-carrier depletion [1] or injection [2] in diode or metal-oxide-semiconductor-(MOS-)structures [3]. However, trade-offs have to be made when aiming at fast devices that feature low drive voltage and small footprint simultaneously.…”

Recent breakthroughs in carrier depletion based silicon optical modulators

“…This approach allows for a large phase shift with voltage with a peak efficiency figure of 2.3 V.cm demonstrated so far [39]. In a different variant of the device modulation at 40 Gbit/s with 10 dB extinction ratio [40] and 50 Gbit/s with a 3 dB extinction ratio [41] has been demonstrated from 3.5 mm long and 1 mm long phase shifters of efficiency ~2.7 V.cm, respectively. The optical loss in the phase modulator is 4 dB/mm excluding passive waveguide loss, with the largest contribution coming from the interaction with the highly doped regions.…”

Integrable microwave filter based on a photonic crystal delay line

“…High-speed intensity modulation on a silicon platform has also been extensively studied in the past years and is still a very active topic. Modulation of 40 Gb s − 1 has recently been achieved within the Helios project consortium with a Mach-Zehnder type device 40 . The electro-absorption modulators in germanium PIN on SOI (silicon on insulator) also exhibit interesting features of high bandwidth (up to 30 GHz), small footprint (a few tens of microns in length), low insertion loss (less than 5 dB) and extinction ratio up to 7 dB (ref.…”