“Broadcast and select” OADM in 80×10.7 Gb/s ultra-long-haul network – Nonlinear and Quantum Optics Lab

This work was done in collaboration with I. Tomkos, M. Mehendale, J.-K. Rhee, A. Kobyakov, M. Ajgaonkar, B. S. Hallock, B. K. Szalabofka, M. Williams, S. Tsuda, and M. Sharma at Corning Inc.

Summary: We report the first experimental realization of dynamically reconfigurable ultra-long-haul network using “broadcast & select” OADM architecture. We achieve 80×10.7 Gb/s NRZ C-band DWDM networking with 50-GHz channel spacing over 4160 km (52 spans x 80 km each) of all-Raman-amplified symmetric dispersion-managed fiber and 13 concatenated OADMs with 320-km spacing. Measured Q values exhibit more than 2 dB margin over the FEC threshold for 10^-15 BER operation. These results are obtained for the channels passing through the 320-km spaced OADMs when 50% add/drop occurs at an intermediate OADM located along the transmission path, as well as for the channels added at the intermediate OADM. Penalties due to filter concatenation and crosstalk are quantified. Q-factor is also characterized after 8000-km transmission.

For details, see the following publications:

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).

Fig. 1. Network scenario modeled in our OADM experiment.

Fig. 2. Schematic of a “broadcast and select” OADM. All input channels are broadcast through a coupler to the drop port where the appropriate drop channels are selected by tunable receivers Rx. In the through pass, these channels are blocked by a wavelength blocker WB, and their corresponding wavelength slots are filled with channels added through a passive coupler.

Fig. 3. Experimental recirculating-loop setup. The loop includes two dynamically-reconfigurable OADMs (A and B paths) to allow adding and dropping channels on the fly. AOS – acousto-optical switches, RA – Raman amplifiers, DMF – symmetric dispersion-managed fiber.

Fig. 4. Q-factor of 80 channels, measured at various points in the network. With FEC gain, the transmission is error-free even at 8000 km, whereas at 4160 km it achieves extra 2 dB performance margin.

Fig. 5. Q-factor sensitivity to transmitter detuning, showing that the effect of concatenation of OADM filters is not significantly impairing our network.

The OADM networking experiment was carried out at Corning Incorporated’s Photonic Research and Test Center in Somerset, NJ.