Exascale computing for Large-Scale Numerical Simulation requires a new technology for optical communication. VCSEL based transmitters run out of bandwidth at 56 Gbps PAM4, and the latency of PAM4 is incompatible with exascale computing. Other available technologies are expensive, have high power consumption, are far from proven or they require PAM4 and temperature control. Our proposed concept integrates an Electro-Absorption Modulator (EAM) with a laser capable of >> 100 Gbps/channel NRZ which can be arrayed to > 1.2 Tbps for a 12 element array and using Course Wavelength Division Multiplexing (CWDM) with 6 wavelengths can reach > 7 Tbps. Using NRZ instead of a more complex format (e.g. PAM4) reduces latency dramatically. The proposed device can operate over a wide temperature range, at least 20C to 100C and potentially over the full military range (-55C to 125C) without temperature control. The characteristic which distinguish our device from traditional Laser-EAM solutions is the extremely short, high absorption, low capacitance EAM which allows significantly higher data rates, lower power and operation over large temperature ranges so TE coolers are not needed. The SE Laser-EAM has a 50% (0.3 pJ/bit vs 0.6 pJ/bit) reduction in power per bit compared to VCSEL solutions. The proposed low cost device can be manufactured by the billions. The SE Laser-EAM array can be flip-chip mounted onto silicon. This unique device has ten times the reach of VCSELs, more than sufficient for any data center or exascale computer. Further, our proposed device has the inherent capability for 300 Gbps NRZ (600 Gbps PAM4) when packaging and IC driver technologies are available.
As the HPSC needs of NASA grow with exascale computing latency, bandwidth, power consumption and footprint ultimately limit the computing performance. The proposed transmitter with the novel SE Laser-EAM solves the latency problem as well as the bandwidth, footprint, and power consumption problems of optical communications in Exascale computing. This is vital to the success of NASA's mission to accelerate delivery of a capable exascale computing system delivering approximately 100× the performance of current systems.
Data centers and HPSC in the US continue moving to single mode fiber data links, and the requirement for low cost, high speed optical transceivers is driving a multibillion dollar component market. The direct sales of our laser/EAM based transmitter would go to optical transceiver integrators such as Menara Networks, Advanced Optical Interconnects (AOI), II-VI, Broadcom and Lumentum.