1. Waveguides: Structures that guide light within the optical circuit. Nanotechnology allows for the fabrication of ultra-compact waveguides with minimal loss. 2. Laser Sources: Nanoscale lasers that emit coherent light. These lasers are essential for data transmission in optical circuits. 3. Detectors: Devices that convert light signals into electrical signals. Nanotechnology enhances the sensitivity and speed of these detectors. 4. Modulators: Components that control the properties of light, such as intensity and phase. Nanoscale modulators offer faster and more efficient modulation.