OPTICAL DEVICE

To provide an optical device including a light receiving unit having high sensitivity for an infrared ray.SOLUTION: An optical device 10 includes a substrate 12, a light receiving unit 20, and a light emission unit 30. The light receiving unit 20 has a first mesa M1, and includes: a first semiconductor layer 21 containing a group III-V compound semiconductor of a first conductivity type; a second semiconductor layer 25 containing a group III-V compound semiconductor of a second conductivity type; and a light absorption layer 23 containing a group III-V compound semiconductor and having sensitivity for an infrared ray. The light emission unit 30 has a second mesa M2, and includes: a first part 30a formed on the substrate 12; and a second part 30b formed on the first part 30a. The first part 30a has a lamination structure the same as the first mesa M1. The second part 30b includes: a third semiconductor layer 38 containing a group III-V compound semiconductor of a first conductivity type; a fourth semiconductor layer 36 containing a group III-V compound semiconductor of a second conductivity type; and a light emission layer 37 containing a group III-V compound semiconductor and emitting an infrared ray.SELECTED DRAWING: Figure 2 【課題】赤外線に対する高い感度を有する受光部を備える光デバイスを提供する。【解決手段】光デバイス１０は、基板１２と、受光部２０と、発光部３０とを備える。受光部２０は、第１メサＭ１を備え、第１導電型のＩＩＩ−Ｖ族化合物半導体を含む第１半導体層２１と、第２導電型のＩＩＩ−Ｖ族化合物半導体を含む第２半導体層２５と、ＩＩＩ−Ｖ族化合物半導体を含み赤外線に感度を有する光吸収層２３とを備える。発光部３０は、第２メサＭ２を備え、基板１２上に設けられた第１部分３０ａと、第１部分３０ａ上に設けられた第２部分３０ｂとを備える。第１部分３０ａは、第１メサＭ１と同じ積層構造を有する。第２部分３０ｂは、第１導電型のＩＩＩ−Ｖ族化合物半導体を含む第３半導体層３８と、第２導電型のＩＩＩ−Ｖ族化合物半導体を含む第４半導体層３６と、ＩＩＩ−Ｖ族化合物半導体を含み赤外線を出射する発光層３７とを備える。【選択図】図２