A 74 Gbps SiGe BiCMOS Electro-Absorption Modulator Driver for Space Applications

This poster presents a radiation-hardened-by-process 74 Gbps electro-absorption modulator driver designed in a 130 nm SiGe BiCMOS technology for application in optical intra-satellite links. The driver is designed to enable optical communications to replace the RF waveguides that are currently used to connect the antennas of a satellite to its interior core. By substituting these waveguides with optical fiber, the size and weight of the connecting networks is significantly decreased, all while allowing for a more flexible and scalable network. However, the outer space environment differs greatly from the terrestrial environment these optical communications devices are typically designed for, mainly because of the presence of both ionizing radiation and high-energy particles. To combat this, several design considerations are taken, and experiments are performed to assess the vulnerability of the driver against radiation exposure in the space environment. The tested samples show little change when irradiated with X-rays up to a total accumulated dose of 1.2 Mrad(Si). During the heavy-ion test, no latchup was observed and transients introduced bit errors at a rate of only 6.4 x10^-13. Both of these experiments demonstrate the radiation hardness of the tested driver, and show that it is indeed suitable to successfully replace the heavy metal waveguides in satellites.