We present the dimensioning of an optical packet switching network for energy-efficient intra-data-center connections. Our approach relies on one or two interconnection stages derived from the time-wavelength-interleaved network concept and relying on fast wavelength-tunable lasers. We compare several options by numerical simulation to increase the bit rate of the intra-data-center links up to 112 Gbit/s. The analysis focuses on pulse-amplitude modulation (4 and 8 PAM), where a pre-distortion mechanism is introduced and three types of optical receivers are taken into account. Possible dispersion of device characteristics is taken into account. The single-stage system should enable us to connect 48 servers using 8 PAM and semiconductor-optical amplifier (SOA)-PIN in conjunction with a 62.5 GHz grid. In the two-stage configuration, this number increases up to 1488.