Design and fabrication optimization of low-crosstalk silicon arrayed waveguide gratings with 32 channels and 100-GHz spacing

Abstract

To satisfy the stringent requirements of large-capacity optical communication systems, the high-performance silicon arrayed waveguide gratings (AWG) with 32 wavelength channels and 100 GHz spacing are designed and fabricated. First of all, three types of arrayed waveguides are designed for seeking better performances, including rectangular-type, arc-type, and S-type ones. During fabrication, the taper connector is then introduced and the waveguide sidewall is further smoothed. Among the samples fabricated using E-beam lithography (EBL), the one with rectangular-type arrayed waveguides is characterized with better performance, showing a crosstalk of −14 dB and an insertion loss of 7.5 dB. Then, the target design with rectangle arrayed waveguides is further optimized and fabricated using 180-nm lithography platform for massive production. Outstanding results are achieved with an insertion loss of 4.5 dB, a channel uniformity of 0.95 dB, and a crosstalk as low as −20.4 dB, respectively. As far as we know, the AWGs might be the first compact silicon one fabricated by commercial lithography platform, characterized by comprehensive specifications (i.e., lowest crosstalk, highest channel uniformity, lowest insertion loss) for massive 100-GHz wavelength multiplexing/de-multiplexing.