Provided is a memory module, a system using the memory module, and a method of fabricating the memory module. The memory module may include a printed circuit board and a memory package on the printed circuit board. The printed circuit board may include an embedded optical waveguide and a first optical window extending from the optical waveguide to a first surface of the printed circuit board. The memory package may also include a memory die having an optical input/output section and a second optical window. The optical input/output section, the second optical window, and the first optical window may be arranged in a line and the first optical window and the second optical window may be configured to at least one of transmit an optical signal from the optical waveguide to the optical input/output section and transmit an optical signal from the optical input/output section to the optical waveguide.