Fiber-coupled photonic interconnects based on stacked glass block connectors

The rapid development of nanophotonic chip devices combines the advantages of ultra-high miniaturization and largescale integrated circuit production, targeting a drastic decrease in the device costs. Such photonic devices based on single-mode waveguide structures are intensively used in optical communications but recently novel high power applications have emerged where it has been demonstrated that nano-sized waveguides support ultra-high optical power densities, giving rise to the generation of non-linear effects. However, all of the applications require a high efficient and stable fiber interface between the chip and the outside world. In this letter, we propose a stacked glass block technology in combination with a sub-micron alignment approach for the development of robust fiber connectors for lateral coupling. This technology offers a high degree of freedom during the assembly of glass parts, compensating undesired misalignments related to the shrinkage of the adhesive. Moreover, adhesive-based issues are minimized by stacking the glass parts with almost zero gap. The design of the glass fiber connector can be adapted for one or more optical fibers. Using an automated laser cutting system, small glass parts from glass panels are cut with high reproducibility and acceptable cut quality. Two different chips for photonic modules of specific output power level with a laser excitation wavelength at 1550 nm are addressed to show the potential use of fiber connectors based on stacked glass blocks.