A record transmission experiment was performed at the PhotonLab by the OptCom group, in cooperation with CISCO Photonics Monza, Oclaro Corporation and Linkra-Teleoptix. The experiment was also partially sponsored by the FP7 European Networks of Excellence EUROFOS and BONE, and by the Istituto Superiore Mario Boella in Turin.

A 1.2 Tbit/s superchannel consisting of ten subcarriers, each carrying 120 Gbit/s, was transmitted to 10,000 km. The transmission format was PM-QPSK at 30 GBaud. The subcarrier spacing was 33 GHz, i.e., 1.1 times the Baud rate. This experiment sets a new record for the parameter (spectral efficiency) x (distance). The previous record was 27000 while this experiment reaches 30000. Z-PLUS^(TM) pure-silica core fiber, provided by Sumitomo Electric Industries, and mixed EDFA-Raman amplification were used.

In a second experiment, 3 Terabit superchannels (30 subcarriers) were sent to 8,000 km (see launched signal power spectrum in figure).

The first Italian and possibly European 1 Tb/s per SuperChannel long-haul experiment was performed at PhotonLab by the OptCom Group, over 2600km.

A  1Tbit/s (1000 Gbit/s) superchannel was successfully transmitted over 2,600 km of installed fiber (a total of 41 spans), with a spectral efficiency of 3.3 b/s/Hz, using 10 PM-QPSK subcarriers spaced at 1.2 times the Baud rate. This results hints at the possibility of transmitting per-fiber capacity on the order 12-15 Tb/s (12000 Gb/s) over the C band and up to 30-40 Tb/s over the C+L bands.

To the left the power spectrum of the superchannel, where the 10 subcarriers are clearly visible. Each subcarrier transmits 100 Gbit/s.

This project is sponsored by the FP7 European Networks of

Excellence and , by FastWeb s.p.a. and by CISCO Photonics. It is also sponsored by

The first Italian implementation of a PDM-8QAM coherent optical transmission systems has been obtained by the OptCom Group at PhotonLab.

Below, the scattering diagrams for the x and y polarizations after DSP at 12.5 Gbaud (75 Gbit/s). The corresponding  OSNR is equal to 18 dB over 0.1 nm.  The plot is at the FEC threshold bit error rate of 1.5e-3.

The transmitter was obtained by a collaboration between our group and the Fraunhofer institute

inside the framework of the project POF-PLUS

The first italian WDM experiment of coherent transmission at 100 Gb/s per channel was performed by OptCom at PhotonLab. A total of 16 channels of 100 Gb/s PM-QPSK (1.6 Tb/s) were transmitted over installed dark fiber over 16 spans, for a total length of more than 1,000 km. Different dispersion maps were tested. Very good performance was obtained, thanks to high-performance modulators and balanced photodetectors.

To the left, the scattering diagram at 1,000 km of the center channel at a launched power of 0 dBm per channel and without any optical dispersion compensation. PM-QPSK confirmed its robustness. to both linear and non-linear impairments.

The experiment was supported by the project

A. Carena, V. Curri, P. Poggiolini, F Forghieri, "Guard-Band for 111 Gbit/s coherent PM-QPSK channels on legacy fiber links carrying 10 Gbit/s IMDD channels", OFC 2009, San Diego (CA), paper OThR7.

Click here to download the Power Point presentation.
 

Transmission of 100 Gb/s PDM-QPSK was achieved by the OptCom Group over installed fiber belonging to the Torino Metro Network of the operator Fastweb, up to 2000 km, using a recirculating loop scheme. 32 recirculations of 63 km each were used. The experiment was carried out in cooperation with the Heinrich-Hertz Istitute (HHI) of Berlin.

This is possibly the first long-haul coherent experiment at 100 Gb/s carried out in Italy. It was sponsored by the EUROFOS project.

The OptCom Group participated in the EUROFOS project plenary meeting that took place in Paris, on Jan 22nd and 23rd. Substantial joint experimental activity on 100Gb/s coherent transmission was agreed upon with major international partners of the EURO-FOS Consortium, to be carried out at PhotonLab. The first results will be available by March 2009. Click on the logo to learn more about EUROFOS.

A prototype of a 100 Gb/s PDM-QPSK coherent optical transmission systems has been built by the OptCom Group at PhotonLab, possibly the first such system implemented in Italy.

Below, the scattering diagrams for the x and y polarizations after DSP. The plot is at the FEC threshold bit error rate of 2e-3. The corresponding ONSR is 15 dB over 0.1 nm.