Multi-quantum well (MQW) spatial light modulator devices are disclosed that are capable of achieving reasonable quantum efficiencies and high contrast ratios in order to close an optical communication link by resolving the logical on or off state. The device both modulates and detects light through the use of the quantum well design and resonant cavity enhancement. Based on the materials (e.g., InGaAs/InAlAs) and their band structures, this device can be configured to communicate in the eye-safe wavelength range (e.g., 1550.+-.20 nm). The device can be fabricated using standard photolithographic processes such as molecular beam epitaxy (MBE) and inductively coupled plasma (ICP) reactive ion etching (RIE).