All-Optical Networking Research in Dr. Vasilyev’s Group
Dynamically reconfigurable optical add-drop multiplexers (OADMs) and cross-connects (OXCs) promise considerable cost reduction in core optical networks. In a typical nation-wide network, only about 25% of the traffic is dropped at each node, and OADMs eliminate the need for expensive optoelectronic regeneration of the remaining 75% by passing this express traffic through. OXCs help in avoiding costly electronic switching fabrics by optically cross-connecting the traffic pipes between different cities.
The use of optical networking, however, comes at the cost of increased penalties due to filter concatenation, crosstalk, amplifier noise, etc., which can considerably reduce the network reach and flexibility. The choice of optimum network architecture and sub-system design therefore becomes critical to the success of optical networking.
We have experimentally demonstrated record-breaking OADM and OXC networking with 80 WDM channels at 10 Gb/s over the distances of up to 8000 km. This work was presented at post-deadline sessions of OFC 2002, OECC 2002, and ECOC 2002, as well as at a number of invited talks. The key enabling technologies in our experiments were “broadcast-and-select” OADM and OXC architectures, symmetric dispersion-managed fiber optimized for Raman amplification, novel spectral pre-emphasis and dispersion mapping approaches and the excellent crosstalk, insertion loss and filter concatenation performance of Corning® Wavelength Blocker performing both the wavelength-blocking and (in OADM experiments) leveling functions. For details, see the following links and publications:
- OADM networking experiments
- OXC networking experiments
- M. Vasilyev, I. Tomkos, M. Mehendale, J.-K. Rhee, A. Kobyakov, M. Ajgaonkar, S. Tsuda, and M. Sharma, “Transparent Ultra-Long-Haul DWDM Networks with “Broadcast & Select” OADM/OXC Architecture,” J. Lightwave Technol. 20, 2661 (2003).
- M. Vasilyev, I. Tomkos, J.-K. Rhee, M. Mehendale, B. S. Hallock, B. K. Szalabofka, M. Williams, S. Tsuda, and M. Sharma, ” “Broadcast & select” OADM in 80×10.7 Gb/s ultra-long-haul network,” IEEE Photon. Technol. Lett. 15, 332 (2003).
The picture above shows the recirculating loop testbed in Dr. Vasilyev’s lab at Photonic Research and Test Center, Corning Inc. (Somerset, NJ). At UTA, we are working on a very similar, but smaller-scale, setup, part of which is shown below.
Ongoing work
Key technologies for scalability and flexibility of future optical networks, both fiber- and free-space-based, are all-optical regeneration and wavelength conversion. Implementing them in a way that scales gracefully with the increased number of WDM channels is a research challenge that we are currently addressing.
The emergence of these all-optical signal-processing methods is creating potential for future deployment of optical burst- and packet-switching networks. The corresponding network and sub-system architectures for ultra-high-speed, wide-bandwidth communication and computing comprise another area of active interest of our research group.