Abstract: Disclosed is a method of producing an electron-absorption modulator having a reverse mesa structure. In the electron-absorption modulator, a first clad of a first conductivity type, an active layer of the first conductivity type, a second clad layer of a second conductivity type and an ohmic contact layer of the second conductivity type are formed on a semiconductor substrate of the first conductivity type. Then, a predetermined mask pattern is formed on the ohmic contact layer. Afterwards, the ohmic contact layer is etched by using the mask pattern. Then, the second clad layer and the active layer below the ohmic contact layer are etched in the form of the reverse mesa structure to expose the first clad layer. Then, the first clad layer is etched at a predetermined depth in the form of a mesa structure.