Semiconductor device

A semiconductor device comprising:

• a substrate comprising a front end face, a rear end face and side faces disposed on both sides of the front end face and the rear end face;
• a plurality of semiconductor lasers provided on the substrate;
• a forward optical multiplexer provided on the substrate to multiplex forward output light of the plurality of semiconductor lasers and output the multiplexed light to the front end face;
• a backward optical multiplexer provided on the substrate to multiplex backward output light of the plurality of semiconductor lasers and output the multiplexed light to the rear end face;
• and
• a plurality of backward waveguides provided on the substrate and connected to an output section of the backward optical multiplexer,
• wherein the plurality of backward waveguides comprise:
• a main waveguide disposed at a center of the output section;
• and
• a plurality of lateral waveguides disposed on both sides of the main waveguide to bend toward the side faces and output light from the side faces diagonally to the side faces.