Semiconductor light-emitting device and optical coupling device

An optical coupling device, comprising:

• a semiconductor light-emitting device comprising:
• a substrate having a first energy bandgap;
• a first semiconductor layer of a first conductivity type provided on the substrate, the first semiconductor layer having a second energy bandgap, the second energy bandgap being wider than the first energy bandgap;
• an active layer provided on the first semiconductor layer, the active layer including at least one quantum well layer and a first barrier layer, the quantum well layer having a third energy bandgap narrower than the first and second energy bandgaps, the first barrier layer being provided between the first semiconductor layer and the quantum well layer;
• and
• a second semiconductor layer of a second conductivity type provided on the active layer, the second semiconductor layer having a fourth energy bandgap wider than the third energy bandgap,
• the substrate having a refractive index greater than a refractive index of the first semiconductor layer at a wavelength of light radiated from the active layer, the refractive index of the first semiconductor layer being not less than a refractive index of the first barrier layer at the wavelength of the light radiated from the active layer;
• and
• a light-receiving element configured to receive the light radiated from the active layer of the semiconductor light-emitting device,
• the substrate of the semiconductor light-emitting device being provided between the active layer and the light-receiving element, the light-receiving element being bonded to the substrate via a resin layer, and the resin layer transmitting the light radiated from the active layer.