Abstract: A device for the control of the output power of laser diodes designed to be coupled to an optical fiber for the tranmission of data comprises a photodiode that can be used to acquire a characteristic signal of the power emitted by the laser diode; digital means to drive the laser diode comprising a central processing unit associated with servo-control computation program memorizing means to keep a constant output power whatever may be the drift and change of slope of the characteristic of the laser diode in response to ageing phenomena or to a change in temperature or to a loss of power due to the coupling of this diode with an optical fiber or to variations in the response of the photodiode as a function of the temperature. Application to digital transmission by optical fiber.