Optical links, manufacturing methods thereof, and memory systems having the same

An optical link, comprising:

• a main optical waveguide;
• N sub-optical waveguides, where N is a natural number;
• N mode couplers, each configured to perform a mode coupling operation between the main optical waveguide and a respective one of the N sub-optical waveguide;
• and
• an optical wavelength filter connected to an output terminal of the main optical waveguide and an output terminal of each of the N sub-optical waveguides;
• wherein each of the N sub-optical waveguides comprises,
• a first region formed at a first distance from the main optical waveguide;
• a second region formed at a second distance from the main optical waveguide, where the second distance is greater than the first distance;
• and
• a third region for connecting the first region and the second region.