Alcatel-Lucent announces successful experiments to substantially increase capacity and robustness of today’s commercial optical networks

Alcatel-Lucent (Euronext Paris and NYSE: ALU) today announced that it has successfully demonstrated the potential for upgrading existing 40Gbit/s transparent long-haul transport networks to 100Gbit/s Ethernet; the use of coherent detection instead of conventional direct detection for unmatched resistance to fiber impairments at 40Gbit/s; the ability to receive and convert serial 107 Gbit/s optical data into lower rate data streams; and the first WDM transmission of channels based on serial binary modulation format exploiting full Electronics Time Domain Division Multiplexing (ETDM). These important optical networking milestones have been presented in several post deadline papers by Alcatel-Lucent’s Bell Labs and Research and Innovation teams at the OFC/NFOEC conference in Anaheim, California this week.

In the first experiment, Alcatel-Lucent’s Bell Labs researchers in New Jersey successfully transmitted ten closely spaced 100 Gbit/s WDM data channels over a 1,200 kilometer optical transmission distance in a systems experiment that included six optical add/drop nodes like those used in today’s transparent mesh networks. Using this design, the researchers achieved an unprecedented spectral efficiency of 1 bit per second per Hertz (b/s/Hz) over the 1200 Km distance using only a single polarization of light. These results demonstrate the practicality of effectively doubling the throughput of today’s commercially deployed optical networks, using WDM channel spacings that are typical of existing and deployed 40G networks using optical and electronic components developed for the 40G market.

Also demonstrated and presented in a post-deadline paper was a project by researchers at Alcatel-Lucent’s Research and Innovation center in Paris on the use of coherent detection to contain distortion and dispersion which happen when sending WDM channels at 40Gbit/s rate over links designed for 10Gbit/s rate. The use of coherent detection instead of conventional direct detection makes the introduction of promising techniques easier, such as using polarisation division multiplexing on top of wavelength division multiplexing, making possible to generate data at 40Gbit/s with just 10Gsymbol/s rate. Based on this approach, an ultra long-transmission over 4080 km has been demonstrated for the first time, highlighting unmatched resistance to fiber impairments, namely PMD and chromatic dispersion, when compared to all other 40Gbit/s proposed solutions.

In a third post-deadline paper, researchers at Alcatel-Lucent’s Bell Labs in New Jersey also demonstrated the ability to receive and convert serial 107 Gbit/s optical data into lower rate data streams with the first fully integrated 107 Gbit/s demultiplexing optical receiver. This optical receiver is unique in that it integrates a 100-Gb/s photodetector with a 1:2 electronic demultiplexer in a single high-speed package. At such high speeds, packaging these two components in an integrated fashion allows for superior performance compared to having separate photodetector and demultiplexer modules. This is a significant step towards the commercial realization of 100 Gbit/s serial transmission systems. Such a compact receiver transforms ultra-high speed optical signals to data rates that are much more manageable in the electrical domain.

In a fourth post-deadline paper, Alcatel-Lucent’s Research and Innovation researchers from Stuttgart demonstrated the Wavelength Division Multiplexing (WDM) transmission of 10 channels, each carrying 107Gbit/s bit rate information over 480km. After a recent single-channel demonstration, this is the first WDM transmission of channels based on serial binary modulation format exploiting full Electronics Time Domain Division Multiplexing (ETDM), both at the transmitter and receiver sides. It is based on advanced research electronic circuits operating at the full line rate. This approach, complementary to the previous ones, prepares the longer-term introduction of 100 Gbit/s systems.