Design and fabrication of conversion fiber with double-core structure for photonic integrated circuits high-density interconnect

Abstract

To relax photonic integrated circuits (PIC) and its optical interconnect densification limitations from the standard fiber, we proposed a special fiber with a double core structure, named conversion fiber, which can convert both its spot size and its outer diameter, simultaneously. The simulation in this study clarified that the proposed conversion fiber had more capability of spot size and the outer diameter conversion with a large conversion ratio, as compared with a conventional fiber with a single core structure, and had large tolerance for the refractive index fluctuation. After that, we fabricated a conversion fiber based on the design parameters. The insertion loss of fabricated conversion fiber, including the coupling loss and the excess loss due to the mode conversion was 0.2 dB, which well agrees with the simulation results. From these results, it is expected that the proposed fiber can achieve higher density optical interconnect for PIC.