Scalable 3D Silicon Optical Switch Based on CLOS Architecture

To achieve complex functionality with small size, weight and power, photonic integrated circuits (PIC) are expanded from two-dimensional (2D) to three-dimensional (3D). In this paper, a new design for a scalable 3D silicon optical switch is proposed. Key elements, including silicon electro-optic switches, crossings, and interlayer transitions are used to define and optimize the 3D optical switching network. The architecture is based on CLOS architecture, which can be extended to multiple layers. Silicon-based two- and three-layer switches are carefully designed and analyzed as an example based on the transfer matrix technique (TMT). In a 4x4 two-layer optical switch, the average insertion loss at 1550 nm wavelength is similar to 4.16 dB, and similar to 3.69 dB for the "all-cross" and "all-bar" states, respectively. In a 4x4 three-layer optical switch, the average insertion loss at 1550 nm wavelength is similar to 5.96 dB, and similar to 5.41 dB for the "all-cross" and "all-bar" states, respectively. The architecture also shows the scalability of both the port number and the layer number. The scalable 3D architecture proposed could improve the interconnect density twice and thrice in a single-layer design.