A memory module having a high data processing rate and high capacity is provided. The memory module may include a memory chip, a controller controlling an operation of the memory chip, an optical detector converting an external input signal into an internal input signal to transmit the converted signal to the controller, and an optical generator converting an internal output signal received from the controller into an external output signal. The optical detector converts an external input optical signal into an internal input signal to transmit the converted signal to the controller. The optical generator converts an internal output signal received from the controller into an external output optical signal.