Thermo-mechanical evaluation of embedded optical interconnects on board

As data rates on backplanes, boards and packages rise, optical interconnections are viewed as a potential technology solution for low power, small footprint, and high speed systems. Some of the challenges with optical interconnect design and development are the introduction of new materials and processes, the increasing bandwidth and decreasing loss requirements, and the need for reducing cost without compromising reliability. The objective of this paper is to understand the thermo-mechanical issues and reliability of optical polymer interconnects for very short-haul backplane, and board/package-level chip-to-chip interconnections. Through finite-element modeling of an embedded photodetector in a waveguide and through reliability experiments, various issues such as contact pad peel stresses, core misalignment, spectral absorption, refractive index stability and thermal stability are examined.