We have developed an experimental 5-Tb/s packet-by-packet wavelength switching system, OPTIMA-2. This paper describes its hardware architecture. OPTIMA-2 is a non-blocking 3-stage switch using optical wavelength division multiplexing (WDM) links and dynamic bandwidth-sharing. A new scheduling algorithm for variable-length packets is used for the receiver ports of WDM links and simulation results show that it can suppress short-packet delay while keeping high throughput. An implementation of the WDM link using field programmable gate arrays and a compact planar lightwave circuit platform is described. Experimental results for the basic operation of optical wavelength switching are also presented.