Optical-microwave interaction has been emphasized in optically reconfigurable antenna arrays (ORA) due to the unique advantage that transparency between the optical control signals and microwave signals makes the antenna less susceptible to jamming. One of the important parts in ORA is an optically controlled microwave switch (OMS) as synaptic elements. A gap-structure OMS has been developed as a low-cost and simple device which operates in all frequencies. However, the OMS is essentially operated in a CW-mode, and adverse effects are observed in the CWmode operation. Although a CW-mode OMS has been investigated previously, a detailed analysis has not been reported. In this paper, we present an analysis, and the numerical simulations are compared with the previous measurements.