Ultra Low Power Consumption Graphene Oxide Infiltrated Subwavelength Waveguide based All-Optical Switch for Tera bit/s Optical Time Division Multiplexing

Driven by bandwidth hungry technologies such as online video and cloud computing, the skyrocketing growth of global data traffic has no sign of halting. The total amount of content passing through the world’s networks will increase from 800,000 petabytes in 2009 to 35 zettabytes in 2020. To meet the world’s endless appetite for bandwidth, dense wavelength division multiplexing (DWDM) system with hundreds of wavelengths has been deployed and proved to be successful. However, including more wavelengths in these systems without sacrificing non-regeneration distance and cost will soon become unrealistic due to nonlinear phenomena and noises. Since each wavelength channel in a DWDM system (usually operates at ~ 10 to 25 Gbit/sec) only uses less than 0.1 percent of its potential capacity, increasing single carrier data rate is an apparent choice. The single carrier data rate is primarily limited by the electronic time division multiplexing (TDM). At data rate beyond 100 Gbps, electronic multiplexing must be abandoned. At ultra-high bit rates beyond 1 Terabits per second (Tbps), it is only possible to perform TDM through all-optical means based on third-order nonlinearity. Plenty material platforms have been investigated, such as silicon-on-insulator and silicon nitride, but so far none of them could meet the speed and low energy consumption requirements satisfactorily. In this proposal, Omega Optics, Inc. and the University of Texas at Austin propose an all-optical TDM system using graphene oxide infiltrated subwavelength silicon waveguide ring resonator with femto-Joule all-optical switch per bit for up to THz region. Due to the extremely large Kerr coefficient of graphene oxide and tight confinement of photons in the subwavelength structure, the nonlinear parameter  of this hybrid waveguide can be as large as 3.9x106 W-1m-1, which is more than four orders of magnitude larger than silicon. Therefore, the switch is capable of achieving Tbps speed with less than 1 fJ energy consumption per bit, which is more than three orders of magnitude smaller than THz switches reported so far. The proposed all-optical TDM, when operates at 1Tbps (~ 1% of the potential single carrier capacity), will increase the bandwidth of current DWDM systems by 100 times, which can meet the bandwidth demand for next 20 years without deploying new fiber cables. Even higher speed can be achieved simply by multiplexing more low speed channels. In addition, benefitting from silicon photonics technology, the proposed TDM system can be mass produced by semiconductor manufacture technologies, which will significantly reduce the cost. As the explosive growth of data traffic continues, the demand on optical TDM is believed to increase substantially. Due to its uniqueness in speed and energy consumption, the proposed TDM is believed to have a vantage position in the market.