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Cedric F. Lam

Cedric F. Lam

Dr. Cedric F. Lam is currently Tech Lead Manager at Google. Before joining Google, he worked at OpVista Inc. as chief system architect, responsible for the development of an ultra-dense WDM transport system with integrated ROADM functionality. Prior to OpVista, Dr. Lam was senior technical staff member at AT&T Labs-Research. His research covers broadband optical transport and access networks architectures, optical signal modulation and transmission, passive optical network, HFC, etc. His current focus is in optical networking technologies for data center applications and Fiber-to-the-Home. Dr. Lam received B.Eng. in Electrical and Electronic Engineering from the University of Hong Kong with First Class Honors and PhD. In Electrical Engineering from UCLA

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    Preview abstract We review state-of-the-art datacenter technologies for 800G, 1.6T and beyond interconnect speeds, focusing on 200G per-lane IM-DD (intensity modulated-direct detect) and 800G-LR1 coherent-lite transmissions. View details
    Preview abstract This is an OIF 800G LR standard contribution. This contribution proposes to revise 800G LR1 baseline link loss budget from 6dB at C-band wavelength to 8dB at O-band wavelength View details
    Preview abstract We review state of art datacenter interconnect technologies for 800G, 1.6T and beyond networking speeds, with a special emphases on 200G per-lane IM-DD and 800G-LR1 coherent-lite View details
    Preview abstract This is intended for IEEE802.3df contribution. In this contribution, we describe the FEC requirements for 800GbE/1.6TbE optics from an operator's perspective, and how to make a fair comparison among different FEC options. View details
    Preview abstract This is intended for IEEE802.3df contribution. In this contribution, we describe how to model four-wave-mixing (FWM) for datacenter interconnects systems, and why FWM could limit the achievable reach for 1.6Tb/s WDM-8 IM-DD systems View details
    800G LR1 Use Cases and Requirements Revisit
    Optical Internetworking Forum, https://www.oiforum.com/, https://www.oiforum.com/ (2021)
    Preview abstract This is contribution of campus networking application requirements to the OIF 800G-LR coherent-lite project. View details
    Preview abstract This is an OFC 2022 conference panel talk. We review from high level about the right technology choice for 1.6Tb/s data center optics interconnects View details
    Long-Reach Wavelength-Routed TWDM PON: Technology and Deployment
    Adam Edwin Taylor Barratt
    Claudio DeSanti
    Daoyi Wang
    Joy Jiang
    Junyan Geng
    Liang Du
    Tao Zhang
    Xiangjun Zhao
    Journal of Lightwave Technology (2019)
    Preview abstract Abstract—We present a long-reach wavelength-routed time-wavelength division multiplexing (TWDM) passive optical network (PON) architecture (LRWR-PON) and its commercial implementation, that supports up to 768 users per fiber strand and up to 50 km transmission distance. The increased reach allows central offices to become more flexible and fewer in quantity, while the increased aggregation reduces the size and number of optical cables needed, enabling smaller trenches to be used. LRWR-PON also contains eight additional point-to-point wavelengths on each fiber to support wireless sites and/or high-speed dedicated bandwidth applications, greatly simplifying converged network designs. Multiple new optical components and modules have been developed to implement our novel architecture. These include a Cyclic Arrayed Waveguide Grating to passively aggregate and distribute access wavelengths in the field, an integrated optical amplifier and multiplexer combination device to aggregate optical line terminal (OLT) channels and extend the system reach, several dense wavelength division multiplexing OLT optics, and a colorless time- wavelength division multiplexing optical network terminal employing ultra-low cost tunable burst-mode lasers. Our analysis shows the simplification of the civil construction enabled by LRWR-PON greatly outweighs the increased optical component complexity. To date, we have conducted a successful field trial with 606 real-life customers for more than 9 months and we have been rolling out this system in new Google Fiber markets for production services. View details
    Preview abstract We discuss the trend in fiber optic technology developments to fulfill the scaling requirements of datacenter networks. View details
    Silicon Photonics for Optical Access Networks
    Pedram Dashti
    Chris Johnson
    Group IV Photonics, IEEE, Washington DC (2012), pp. 3
    Preview abstract We highlight promising developments and directions in silicon photonics for realizing cost effective WDM-PON: photonic integration for integrated WDM transceivers at the OLT and widely tunable laser technologies for achieving a high performance, colorless ONU. View details
    High Performance, Low Cost, Colorless ONU for WDM-PON
    Chris Johnson
    Optical Fiber Communication (OFC) Conference 2012, OSA, Washington DC
    Preview abstract We give an overview of key technologies for realizing WDM-PON. In particular, we highlight promising developments and directions in widely tunable laser technologies for achieving a high performance, colorless ONU at the cost points required for access networks. View details
    Drivers and applications of optical technologies for Internet Data Center networks
    Paul Schultz
    Optical Fiber Communication Conference and Exposition (OFC/NFOEC), 2011 and the National Fiber Optic Engineers Conference, pp. 1-3
    Preview abstract The rise of large-scale Data Centers to power the Internet infrastructure is driving new architectural directions for optical networking. This paper highlights these architectural options and discusses technology building blocks for scaling inter-Datacenter connectivity. View details
    Field verification of 40G DPSK upgrade in a legacy 10G network
    Valey Kamalov
    Xiaoxue Zhao
    Optical Fiber Communication, IEEE (2010), NTuC2
    Preview abstract We report verification of 1,200 km field upgrade of 10 G NRZ wavelengths with 40 G DPSK channels. Non symmetric dispersion map results in pronounced intra-channel nonlinear effect, which could be significantly reduced by dispersion pre-compensation View details
    Preview abstract We review the trade-offs, challenges and potentials of various FTTH architecture options. View details
    Scaling Optical Interconnects in Datacenter Networks Opportunities and Challenges for WDM
    Chris Johnson
    2010 18th IEEE Symposium on High Performance Interconnects, IEEE, pp. 113-116
    Preview abstract We review the growing need for optical interconnect bandwidth in datacenter networks, and the opportunities and challenges for wavelength division multiplexing (WDM) to sustain the “last 2km” bandwidth growth inside datacenter networks. View details
    100GbE and Beyond for Warehouse Scale Computing
    Vijay Vusirikala
    Vijay Gill
    OptoeElectronics and Communications Conference (OECC) Technical Digest (2010), pp. 106-107
    Preview abstract As computation and storage continues to move from desktops to large internet services, computing platforms running such services are transforming into warehouse-scale computers. 100 Gigabit Ethernet and beyond will be instrumental in scaling the interconnection within and between these ubiquitous warehouse-scale computing infrastructures. In this paper, we describe the drivers for such interfaces and some methods of scaling Ethernet interfaces to speeds beyond 100GbE. View details
    Fiber Optic Communication Technologies: What’s Needed for Datacenter Network Operations
    Xiaoxue Zhao
    Valey Kamalov
    Vijay Gill
    IEEE Communications Magazine, vol. Vol.48 No.7 (2010)
    Preview abstract The authors review the growing trend of warehouse-scale mega-datacenter computing, the Internet transformation driven by mega-datacenter applications, and the opportunities and challenges for fiber optic communication technologies to support the growth of mega-datacenter computing in the next three to four years. View details
    Wireless Techniques in Optical Transport
    Proceedings of the 14th Optoelectronics and Communications Conference (2009)
    Preview abstract Abstract The field of optical communications is undergoing a transformation from analog to digital. Advanced signal processing techniques which have been widely used in wireless communications and local access loops are now being applied to long haul optical transmission networks. In this paper, we discuss the implications of such transformations and postulate a new paradigm for optical transport in future high speed optical backbone networks. View details
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