Abstract: A photon detection device having a high light detection efficiency. The photon detection device includes a first light reception part which receives a gate signal and outputs a first signal; a second light reception part which receives a gate signal and outputs a second signal; and a determination part which determines whether or not a photon is received, on the basis of the first signal from the first light reception part and the second signal from the second light reception part. The photon is incident on the first light reception part among the first light reception part and the second light reception part, and the breakdown voltage of the second light reception part is higher than the breakdown voltage of the first light reception part.

Abstract: An avalanche photodiode includes: a first contact layer; a light absorbing layer located on the first contact layer and having a multi-quantum well structure; a first electric field control layer located on the light absorbing layer; and a carrier multiplication layer located on the first electric field control layer. At least one of the multi-quantum well structure includes a well layer that includes Ga1-xAlxN (0?X?0.3), and a barrier layer that includes Ga1-xAlxN (0.7?X?1) and a doping portion doped with a p-type dopant.

Abstract: An optical integrated circuit comprises optical waveguides, grooves formed by etching the upper cladding layer, the core layer and all or parts of the lower cladding layer close to a end section of the optical waveguide to intercept light transmitted through the core layer of the optical waveguide or to couple light into the core layer, a plurality of bonding pads formed around the groove, micro-mirrors and active optical elements. Such a PLC based optical integrated circuit and a method of manufacturing the same provides a low-cost manufacturing of optical integrated circuits and high quality mirrors for vertical optical coupling scheme.