Abstract
The co-packaging of optics and electronics provides a potential path forward to achieving Pbps per package data capacities. In a co-packaged design, the scaling of bandwidth, cost, and energy is governed by the number of optical tranceivers per package as opposed to transistor shrink. The scaling of optical transceivers is hindered by the need to actively assemble bulky single mode fiber arrays directly to optical transceivers. The development of efficient, dense optical couplers with wide alignment tolerances allowing for automated, passive assembly will be an enabler for continued scaling in co-packaged designs. To this end, a passively assembled substrate-to-die evanescent coupler between silicon nitride and silicon was experimentally demonstrated with a 0.39 ± 1.06 dB coupling loss at 1550 nm, a 160 nm 1-dB wavelength tolerance (1480–1640 nm), and a 1-dB lateral alignment tolerance of ± 1.56 μm. The thermal stability was evaluated from 23–60°C with average coupling loss and alignment tolerance varying by less than ± 0.35 dB and ± 30 nm, respectively. Finally, repeatability was evaluated across four packaged systems, demonstrating a coupling loss range of 1.5 dB. Together, these results show this coupler can help achieve Pbps co-packaged optics input/output (I/O) within a sustainable envelope.
