Wednesday, March 31, 2010

Alcatel-Lucent's Bell Labs Describes Single-Carrier 224 Gbps

Researchers from Alcatel-Lucent's Bell Labs demonstrated a range of technology advances at last month's Optical Fiber Conference (OFC) in San Diego, California, including higher-order modulation techniques, use of multi-stage algorithms and increased spectral efficiencies that enable the transmission of significantly higher bit rates over increasingly longer distances. The optical transmission technologies demonstrated by Bell Labs were presented in a series of juried research papers reviewed in rigorous evaluation process and accepted by the OFC program committee. Alcatel-Lucent highlighted the following items:

Field transmission of optical OFDM1 signals carrying greater than 100 Gbps -- A key step forward in the evolution of new modulation formats over existing fiber infrastructure. Involves transmission of 3x253Gb/s OFDM-Superchannels over 764 km field deployed single mode fibers. Employs ten G.652 fiber spans, provided by Deutsche Telekom AG and makes use of OFDM channels spaced 100GHz apart that cover a bandwidth of 90GHz and result in a configuration compatible with a 100GHz grid.

Next-Generation 400 Gigabit per second transmission -- Generation and detection of a novel spectrally-efficient format occupying a bandwidth of only 60 GHz. Involves 448-Gbps Reduced-Guard-Interval CO-OFDM Signal with 7 bit-per second-Hz channel spectral efficiency and transmission over 2000-km of ULAF and five 80-GHz-Grid optical add-drop multiplexers.

40% increase of single-carrier bit rate, up to 224-Gbps -- An improvement over the highest previous 20 Gbaud (160 Gbps) single-carrier line rate demonstrated in PDM 16-QAM transmission. Single-carrier multilevel modulation at high symbol rates enables a simpler transmitter structure. Involves a 10 × 224-Gb/s WDM Transmission of 28-Gbaud PDM2 16-QAM on a 50-GHz Grid over 1,200 km of fiber.