In this paper, we propose a novel optical pyramid data center network architecture (OPMDC), achieving scalable and high bandwidth, low latency, and reduced power consumption and wiring complexity. Based on an incremental and modular design, a full-scale OPMDC is built on three types of WSS-based optical switching nodes in three tiers. These optical nodes are recursively interconnected according to a pyramid structure parameterized by the number of nodes (B ) at the base. Such a pyramid-based topology facilitates horizontal mesh connections that are tailored to achieve flexible optical packet-based transport. To this aim, we design a wavelength scheduling algorithm, called most-contentious-first, augmented with source and destination relay and aggregation (SDRA) via the horizontal mesh connections in the source and destination pods. Simulation results show that employing SDRA results in a vast improvement of throughput from 42.5% to 87.9% at full load, at a cost of no more than two additional hops of latency. Further, we present our OPMDC ($B = 7$) prototype and provide performance assessment and the measurements of packet latency. Finally, experimental results show that after travelling the longest possible path with six optical nodes in OPMDC, the signal suffers no accumulated distortion and noise from the cascades of WSS and EDFA modules.