Artificial gauge field enabled low-crosstalk, broadband, half-wavelength-pitched waveguide arrays

Abstract: Dense waveguide arrays with half-wavelength-pitch, low-crosstalk, broadband, and flexible routing capability are essential for integrated photonics. However, achieving such performance is challenging due to the relatively weaker confinement of dielectric waveguides and the increased interactions among densely packed waveguides. Here, leveraging the artificial gauge field mechanism, we demonstrate half-wavelength-pitched dense waveguide arrays, consisting of 64 waveguides, in silicon with -30dB crosstalk suppression from 1480nm to 1550nm. The waveguide array features negligible insertion loss for 90-degree bending. Our approach enables flexibly routing a large-scale dense waveguide array that significantly reduces on-chip estate, leading to a high-density photonic integrated circuit, and may open up opportunities for important device performance improvement, such as half-wavelength-pitch OPA and ultra-dense space-division multiplexing