OPTICAL WAVEGUIDE, OPTO-ELECTRIC HYBRID SUBSTRATE AND ELECTRONIC APPARATUS

PROBLEM TO BE SOLVED: To provide an optical waveguide having high optical coupling efficiency with a light-receiving/emitting device and allowing high quality optical communication even with high density, and a highly reliable opto-electric hybrid substrate and an electronic apparatus equipped with the optical waveguide.SOLUTION: An optical waveguide 1 comprises: core layers 131, 132 having a core unit 14 and a side face clad unit 15 adjacent to the core unit 14; a lamination body 12 obtained by alternately laminating clad layers 111, 112, 113 so as to include two or more of the core layers; and mirrors 1611, 1612, 1613, 1614 provided on a first optical path being an optical path of the core unit 14, and configured to convert the first optical path so as to be optically connected at a node 121 of the lamination body 12 by optical reflection. The optical waveguide 1 is configured such that the first optical path crosses a second optical path that connects the node 121 and the mirrors, and further comprises a low refractive index layer 145 having lower refractive index than the core unit 14, and extended along the second optical path in vicinity of the crossing core unit 14.