Final Report Summary - SOCRATES (Serial Optical Communications for Advanced Terabit Ethernet Systems)
The ERC SOCRATES project (Serial Optical Communications for Advanced Terabit Ethernet Systems) began in September 2009, and from the beginning it sat out to push the limits of what had been shown possible with serial optical communications. Already within the first year, the SOCRATES team managed to demonstrate breaking a 10 year long standing record of how high a serial bit rate could be generated, transmitted and detected. The standing record had been fixed at 640 Gbit/s (single polarisation, binary modulation) for 10 years. The ERC SOCRATES team doubled that by demonstrating 1.28 Tbit/s serial data generation with intact data reception, and soon followed that by transmitting it, first over 50 km of fibre, and later 100 km – still the longest transmission demonstrated with Tbaud class data. Adding the polarisation and quaternary dimensions, the team soon showed 5.1 Tbit/s data generation. The idea here was always to attempt to put as much data as possible on the light from a single laser, and in the serial approach, very short pulses of around 300 fs duration were used to carry data in two polarisations and with four phase levels imprinted on them as data. Later, in collaboration with German partner Fraunhofer Gesellschaft Heinrich Hertz Institute in Berlin, the SOCRATES team could push it up to 10 Tbit/s by using more advanced data modulation, so called 16 QAM. This remains the serial data rate record. Since then, other methods of using the light from a single laser to carry high data loads were investigated. And in the final year of SOCRATES, in a collaboration with NTT in Japan, it was shown that 43 Tbit/s could be carried on the light from that single laser. This is the highest reported data rate ever to be carried by a single laser. In this experiment, novel multi-core transmission fibre supplied by NTT was used in conjunction with advanced multiplexing in five dimensions: polarisation and quaternary modulation as mentioned above, as well as spectral Nyquist-channel multiplexing and optical time domain multiplexing (OTDM), and finally the spatial dimension was used through the multi-core fibre. This achievement was elected to be put on the Top-20 of the greatest engineering feats of 2014 by engineerjobs.com with an entry as no. 7: . http://www.engineerjobs.com/magazine/2014/20-greatest-engineering-feats-2014.htm?utm_content=buffer455c4&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer.
The SOCRATES project furthermore wanted to explore the concept of creating data packets carrying extreme bit rates, up to 1 Tbit/s. This was achieved by demonstrating the first-ever 1.28 Tbit/s packet switching using a novel scalable in-band labelling scheme taking advantage of the relative broad spectrum of the short data pulses.
Also, the SOCRATES team demonstrated the first synchronisation of Tbit/s data packets to a local master clock using an optical time lens setup, allowing for packet switching at remote nodes.
Developing this optical time lens scheme further has led the SOCRATES team to realise units than can convert from serial to parallel and vice versa, as well as process spectrally efficient data formats like orthogonal frequency division multiplexing (OFDM) signal and Nyquist wavelength division multiplexed (WDM) signals. For instance, the team could demonstrate a record 1 bit/s/Hz binary spectral efficiency when creating a 1.28 Tbaud, 1.28 Tbit/s Nyquist-OTDM data signal taking up exactly the minimum 1.28 THz of bandwidth, and the perform a serial-to-parallel conversion using a time lens of this data signal. This 1.28 Tbit/s N-OTDM data signal was used to transmit over the record distance for Tbaud symbol rate of 100 km.
The above results have given rise to many high-profile publications, not least 9 postdeadline papers at leading conferences.
The SOCRATES project furthermore wanted to explore the concept of creating data packets carrying extreme bit rates, up to 1 Tbit/s. This was achieved by demonstrating the first-ever 1.28 Tbit/s packet switching using a novel scalable in-band labelling scheme taking advantage of the relative broad spectrum of the short data pulses.
Also, the SOCRATES team demonstrated the first synchronisation of Tbit/s data packets to a local master clock using an optical time lens setup, allowing for packet switching at remote nodes.
Developing this optical time lens scheme further has led the SOCRATES team to realise units than can convert from serial to parallel and vice versa, as well as process spectrally efficient data formats like orthogonal frequency division multiplexing (OFDM) signal and Nyquist wavelength division multiplexed (WDM) signals. For instance, the team could demonstrate a record 1 bit/s/Hz binary spectral efficiency when creating a 1.28 Tbaud, 1.28 Tbit/s Nyquist-OTDM data signal taking up exactly the minimum 1.28 THz of bandwidth, and the perform a serial-to-parallel conversion using a time lens of this data signal. This 1.28 Tbit/s N-OTDM data signal was used to transmit over the record distance for Tbaud symbol rate of 100 km.
The above results have given rise to many high-profile publications, not least 9 postdeadline papers at leading conferences.