A multibeam coherent laser diode source comprises a master laser, a linear amplifier and two perpendicular amplifiers. The master laser and amplifiers are in the form of a single heterostructure containing an active layer, two limiting layers and a radiation influx area with an influx layer. The heterostructure is characterized by the ratio of the refractive index of the heterostructure to the refractive index of influx layer. This ratio is determined from a range extending from one plus delta to one minus gamma, where delta and gamma are defined by a number much less than one and gamma is greater than delta. The linear amplifier is positioned so that optical axis of radiation propagation from master laser coincides with the axis of the linear amplifier. Each perpendicular amplifier has output edge and is positioned so that its optical axis is situated at right angle to the axis of linear amplifier.