Optical waveguide and electronic device

2:

• The optical waveguide according to claim 1,
• wherein a refractive index distribution P in the layer-stacking direction, in a portion which ranges from the first cladding layer through the cladding section to the second cladding layer, appears differently in a portion located at the first cladding layer and in a portion located at the cladding section.

3:

• The optical waveguide according to claim 1,
• wherein the refractive index distribution T in the layer-stacking direction, in a portion which ranges from the first cladding layer to the first core section, is different from the refractive index distribution W.

4:

• The optical waveguide according to claim 1,
• wherein a difference between the maximum value of refractive index of the first core section and the maximum value of refractive index of the first cladding layer, is larger than a difference between the maximum value of refractive index of the first core section and the maximum value of refractive index of the cladding section.

5:

• The optical waveguide according to claim 1, further comprising a second core layer provided over the second cladding layer, and
• the second core layer has a third core section located above the first core section in the layer-stacking direction.

6:

• The optical waveguide according to claim 1,
• wherein the refractive index at the bottom of the first dip is smaller than the average refractive index of the cladding section.

7:

• The optical waveguide according to claim 1,
• wherein the refractive index distribution W shows the apex of the second peak at a portion other than the vicinity of the boundary between the first core section and the cladding section.

8:

• The optical waveguide according to claim 1,
• wherein the refractive index distribution W shows the apex of the second peak at the center portion of the cladding section, and has a region in which the refractive index continuously decreases from the apex of the second peak towards the first dip.

9:

• The optical waveguide according to claim 1,
• wherein the difference between the refractive indices of the first core section and the first cladding layer in the refractive index distribution T, is larger than a difference between the refractive indices at the bottom of the first dip and at the apex of the first peak in the refractive index distribution W.

10:

• The optical waveguide according to claim 1,
• further comprising a space provided so as to extend across the first core section and the first cladding layer, with an inner surface thereof being configured as a reflective surface on which light which propagates through the core section is reflected.

11:

• The optical waveguide according to claim 1,
• wherein a difference between the refractive indices at the bottom of the first dip and the average refractive index of the cladding section, is 3 to 80% of a difference between the refractive indices at the bottom of the first dip and at the apex of the first peak.

12:

• The optical waveguide according to claim 1,
• wherein a difference between the refractive indices at the bottom of the first dip and at the apex of the first peak is 0.005 to 0.07.

13:

• The optical waveguide according to claim 1,
• wherein, in the refractive index distribution W, defining a [μm] to be the width of a region of the first peak, over which the refractive index is not smaller than the average refractive index of the cladding section, and defining b [μm] to be the width of a region of the first dip, over which the refractive index is smaller than the average refractive index of the cladding section, then b is 0.01a to 1.2a.

15:

• An electronic device having the optical waveguide described in claim 1.