|Thread Links||Date Links|
|Thread Prev||Thread Next||Thread Index||Date Prev||Date Next||Date Index|
I have recently joined this reflector, and I would like to make one observation which may be of benefit to the group. However, please forgive me if I speak out of turn, am confused about some of the acronyms or cover material already agreed.
There appears to be some considerable debate relating to the trade-off
between reach, data rate, buffer requirements and the capabilities of electronics
with manufacturability at a reasonable cost. This has lead to the M lanes at
I would like to propose the HSSG to consider the use of a new modulation format, currently known as “Coherent WDM”, in order to simultaneously meet all of these requirements. In Coherent WDM, we use a single laser source, minimizing inventory. This source is either a mode locked source, producing multiple carriers, or a standard cw source followed by at least one sine wave driven modulator (10 GHz in this example) in order to generate an optical carrier for each lane. These carriers are then modulated using an array of modulators (one for each lane, and each driven at 10 Gbit/s in this example), with, for example, a PIC similar to the one proposed by Drew Perkins. This produces a single 100 Gbit/s (in this example) signal, occupying a small spectral width of very close to 110 GHz which is transmitted as a single entity over a link (either point-to-point or a WDM network). The compact spectrum and careful design of the PIC and drive circuits combine to give negligible skew between the lanes, minimizing buffer requirements. You thus obtain the key features of the high serial data rates. It has been demonstrated that the reach of a Coherent WDM system is dominated by effects proportional to the data rate of each lane rather than the total data rate, and 10 Gbit/s electronics may be used. You thus also obtain the key features of a high lane count, low serial data rate link.
I would be very happy to provide further details of Coherent WDM should anybody reading this contribution feel that it is appropriate.
Thank you for your attention
Senior Research Fellow
Photonic Systems Group
Tyndall National Institute and Department of Physics
Phone: +353 21 490 4858
Fax: +353 21 490 4880
web site: www.tyndall.ie/research/photonics-systems-group/index.htm