Optical interconnect can achieve a substantial increase in the number of nodes and switching capability for data centers, by virtue of their low power consumption and high bandwidth. In this paper, we propose a single-wavelength switch architecture based on two-stage AWGR for data centers. Then the single-wavelength design is extended to support multi-wavelength, which has higher scalability but lower hardware complexity and power consumption. We prove that the single wavelength architecture is internal strictly non-blocking. When the incoming traffic is externally blocked, a buffer allocation algorithm is designed to allocate feedforward and feedback FDL for the blocked packets. Based on the simulation results, the proposed switch can provide higher throughput, lower average latency, and a 0 out-of-order ratio compared to existing solutions.