Vertical Silicon-on-Insulator Coupler for High Density Optical Interconnects

We present an ultra-compact dual-polarization coupler working at normal incidence to the chip surface for use with multi-core fibers with a core-to-core spacing down to 15µm. The coupler achieves an unprecedented efficiency of −3.8dB for a device with a footprint of only 100µm ² and a 3-dB bandwidth of 59nm.