Large-Scale Optical-Switch Prototypes Utilizing Cyclic Arrayed-Waveguide Gratings for Datacenters

We propose novel large-scale optical-switch architectures that utilize delivery and coupling (DC) switches and wavelength routing (WR) switches based on the cyclic arrayed-waveguide gratings (AWGs). To suppress the passband-frequency deviation inherent in cyclic AWGs, we propose two-stage WR structures in which multiple small-scale cyclic AWGs are cascaded to create a large-scale WR switch. We introduce two configurations for constructing a WR switch; the degrees of the first- and second-stage cyclic AWGs are coprime or not. We fabricate both types of optical switches with planar lightwave circuit technologies. A 270 × 270 switch comprised of coprime cyclic AWGs and a 180 × 180 switch comprised of cyclic AWGs whose degrees have a common divisor are compactly fabricated. Transmission experiments confirm their excellent performance.