To provide an integrated interferometer structural body having peripheral amplifiers which may be operated even in a nonsaturated state.

The first and second branches of the structural body having at least one first semiconductor optical amplifier (OA1) are connected to peripheral semiconductor optical amplifiers (OA4, OA5) on an inlet side and/or peripheral semiconductor amplifier (OA3) on an outlet side. This structural body is characterized by having an attenuation section (10) between the output of at least one amplifier (OA1) of one of the branches and the input of the peripheral amplifier (OA3) on the outlet side and/or by that the length of the waveguide of at least one peripheral amplifiers (OA3, OA4, OA5) is shorter than 300 μm. This structural body is used for the field of communication and above all, route assignment of signals.