Low cost 500Gbps transmission for datacenter applications

This paper describes the development of a transmitter and receiver leveraging a combination of monolithic and hybrid integration for Datacenter applications to deliver 500Gbps over 2km on a single mode fiber. The transmitter encompasses 12 electro-absorptive modulated lasers (EMLs) with wavelength channels from 1270nm to 1380nm on a 10nm channel grid. The lasers are grouped in three (3) arrays with each array monolithically integrating four (4) EMLs operating at 43Gbps each. The three EML arrays are flip-chip bonded to a planar light-guide circuit (PLC), which serves as the mounting platform and provides the optical multiplexer function. The receiver couples the signal through an optical PLC-based de-multiplexer to twelve (12) high-speed PIN detectors with a 3dB bandwidth of more than 50GHz. The transmission tests were performed over 2km of SMF with each channel tested at 40Gbps. For the demonstration, a commercial semiconductor optical amplifier was used in front of the receiver to boost the signal. Each channel was tested to be error free to −11 BER with most −12 BER. The total cross-talk was measured to be between 1 and 2dB. The channel spacing of 10nm was chosen to enable a low cost transmitter operation without using Thermo-Electric-Coolers (TEC) in order to reduce the overall power dissipation. Instead of a TEC, resistive heating can be used to limit the temperature excursions and to enable an operating range of the TOSA from −5 to +75 deg C. This technology demonstration is a step towards the final goal of 1 Terabit/s transmission for Datacenter applications.