Artificial Gauge Field Enabled Low‐Crosstalk, Broadband, Half‐Wavelength Pitched Waveguide Arrays

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, half‐wavelength‐pitched dense waveguide arrays, consisting of 64 waveguides, in silicon with −30 dB crosstalk suppression from 1480 to 1550 nm are demonstrated. The waveguide array features negligible insertion loss for 90° bending. This 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 optical phased array and ultra‐dense space‐division multiplexing. Dense waveguide arrays are essential for on‐chip integrated photonics, enabling high‐density integration and superior device performance. Half‐wavelength pitched dense waveguide arrays with low‐crosstalk and broadband are experimentally demonstrated by introducing an artificial gauge field (AGF). Leveraging the AGF‐induced additional phases, the crosstalk inside half‐wavelength‐pitched waveguide arrays is significantly suppressed and broadband and low insertion loss are achieved simultaneously.