On-Chip Wavelength Multicasting of 3×320-Gb/s Pulsed-RZ Optical Data

We demonstrate for the first time on-chip wavelength multicasting of 320-Gb/s pulsed-RZ data. Using four-wave mixing in a dispersion-engineered silicon waveguide, we perform a 3× multicast, verify full selectivity, perform spectral evaluation, and record eye diagrams for the wavelength-multicasted signal. Introduction Recent advances in silicon photonics have given this integrated platform the potential to enable orders-of-magnitude performance gains in highperformance communication applications, including next-generation optical telecommunication networks, data center interconnection networks, and even photonic networks-on-chip 1 . Endowed with complementary metal-oxide-semiconductor (CMOS) compatibility, silicon-on-insulator (SOI)based photonic integrated circuits (PICs) are capable of direct integration with advanced microelectronics, with a clear path toward highvolume low-cost mass production. SOI-based PICs utilizing nonlinear optical processes leveraging four-wave mixing (FWM) have enabled many all-optical functionalities, including wavelength conversion 2 , wavelength multicasting 3 , spatial multicasting 4 , and temporal demultiplexing 5 , all on chip. Furthermore, dispersion engineering of these devices enables ultrahigh-bandwidth operation 6 . Future high-performance optical networks will vastly benefit from replacing power-hungry transceivers between nodes with all-optical processes for routing, multicasting, and demultiplexing. Moreover, these processes must sustain the massive bandwidth growth offered by both wavelength-division multiplexing (WDM) and time-division multiplexing (TDM). Using FWM in highly-nonlinear fiber (HNLF), wavelength multicasting of 320-Gb/s data was recently demonstrated with self-seeded pumps 7 . In this work, we demonstrate on-chip wavelength multicasting of 3×320-Gb/s pulsedRZ data using a dispersion-engineered silicon waveguide. By selectively toggling the states of the optical input signals, we perform full multicast selectivity, demonstrating all possible states of this 3× multicast. Furthermore, we derive critical performance metrics based on spectral evaluation, and validate the high-speed optical data using eye diagrams. Experimental setup The dispersion-engineered silicon waveguide in this work has a length of 1.1 cm, height of 290 nm, slab thickness of 25 nm, and width of 720 nm. In the experimental setup using this device, we first generate a 320-Gb/s pulsed-RZ pump signal, combine it with up to three CW wavelength channels, launch the combined signals into the silicon waveguide, and finally extract the signals, examining the resulting wavelength multicasting (Fig. 1). The 320-Gb/s pump signal is generated using a 10-GHz modelocked laser (MLL), producing 1.5-ps optical pulses, which is first multiplexed to 40 GHz using four-fold (4×) optical time-divisionmultiplexing (OTDM) stages. The 40-GHz pulse Fig. 1: Diagram of experimental setup used for the 3×320-Gb/s wavelength multicast. ECOC 2010, 19-23 September, 2010, Torino, Italy 978-1-4244-8535-2/10/$26.00 ©2010 IEEE We.7.E.3