Keysight and McGill University 1.6Tbps O-band coherent transmission over 10km

AI, 5G, and IoT applications are driving the demand for more bandwidth in optical networks. Leveraging high symbol rate systems increases the aggregate per-wavelength data rate to reduce the cost-per-bit in optical systems. A key trend in data centres is the transition to higher symbol rates through integrated optics, which reduces the component count, cost, and power consumption.

To address growing short-reach intra-data centre traffic demands -- from two to 10km – coherent transmission systems are being considered as an alternative to intensity modulation direct detection (IMDD) systems that are currently operating at 200Gbps per wavelength over 2km in the O-band. Low chromatic dispersion makes power-efficient coherent links an attractive replacement for IMDD technologies at 1.6Tbps and beyond.

To demonstrate improvements in short-reach intra-data centre transmission rates using a coherent O-band solution, Keysight, McGill University, and other research partners collaborated to achieve record-breaking transmission. The demonstration system consisted of Keysight's new M8199B 256 GSa/s Arbitrary Waveform Generator that delivers 75GHz bandwidth in combination with a thin-film lithium niobate I/Q modulator with 100 GHz bandwidth and a 110GHz 256 GSa/s Keysight Infiniium UXR-Series Oscilloscope. The accomplishment showcased how data centers can use coherent optical fibre transmission systems operating at 167Gbaud, using dual-polarization, 64-quadrature amplitude modulation scheme to transmit signals at 1.6Tbps in the O-band using DFBs for the carrier and local oscillators. 

McGill University Professor and Canada Research Chair David V. Plant said: "The McGill University research team is very proud to be working with the test and measurement leader Keysight, and our partners, all of whom contributed to achieving this new record. The breakthrough was accomplished by using the latest technologies, including Keysight's recently announced and most powerful Arbitrary Waveform Generator. This achievement is a significant demonstration on the path to consolidating short-reach, O-band, coherent optical fibre transmission systems for data centre interconnect applications."