Coupling device and electronic device including the same

An electronic device comprising:

• a coupling device;
• an optical fiber array connected to a first end of the coupling device;
• and
• a photonic integrated circuit connected to a second end of the coupling device,
• wherein the coupling device comprises:
• a substrate comprising a first surface, a second surface, and a third surface, wherein the first surface and the second surface face away from each other, and the third surface is between and connected to the first surface and the second surface;
• and
• a coupling waveguide within the substrate and extending from the first surface to the second surface,
• wherein the coupling waveguide comprises:
• a first waveguide in the third surface, the first waveguide comprising a first end portion and a second end portion, wherein the first end portion is exposed at the first surface, the second end portion is inside the substrate, and the first waveguide further comprises a transmission path from the first end portion to the second end portion in a first direction parallel to the third surface;
• and
• a second waveguide comprising a third end portion and a fourth end portion, wherein the third end portion is adjacent to the first waveguide within the substrate, the fourth end portion is exposed at the second surface, and a distance from the third surface to the third end portion is different from a distance from the third surface to the fourth end portion.