Recently, the energy consumption in data centers is increasing. Introducing optical circuit to the inter-rack communication is considered as an effective solution. The authors are working on the research and development of the High-speed Optical Layer 1 Switch system for Time slot switching based optical data center networks (HOLST). We focused on Plomb Lanthanum Zirconate Titanate (PLZT) optical switch that performs nano seconds switching time. In this paper, several ideas on how to connect PLZT optical switches and Micro Electro Mechanical Systems (MEMS) optical switches, the composing modules of the HOLST, are proposed to design network architecture and evaluated in order to compare and consider power saving effect. The result of the numerical simulation shows that the proposal architecture achieves 50% energy consumption reduction than the conventional architecture.