Thermal Stability of Optical Coupling Solutions in Silicone-Based Optical Interconnects

The thermal stability of different coupling solutions (butt coupling and mirror coupling) in polymer optical interconnects has been investigated by means of the finite volume method based software, FLOTHERM. According to this approach, thermal simulations are performed to study and compare the thermal behavior of vertical-cavity surface-emitting diodes (VCSELs), photo diodes (PDs), and polymer waveguide layers within polymer optical interconnects with different coupling solutions. In the case of butt coupling, the maximum temperatures on the VCSEL and PD chips, as well as the influence caused by changes of the optical interconnect length, are discussed. In the case of mirror coupling, temperature distributions and gradients in the key waveguide layer are analyzed and also compared with optical interconnects using butt coupling. With this simulated temperature distribution and the experimentally evaluated refractive indices and thermooptic coefficients of core and cladding silicones, the influence on the maximum data transmission capability in silicone-based waveguides is discussed, as well as the impact on waveguide insertion loss figures at 850 nm.