Device for stabilizing the output power of a transmitter module in an optical fiber transmission system

A device for stabilizing the output power of a transmitter module in a data transmission system which utilizes an optical fiber and comprising:

• a unit in which are disposed a laser diode, means for taking a part of the optical output power produced by the laser diode and for converting optical power to electrical power;
• a first circuit for stabilizing the mean value of the optical output power produced by said laser diode, said circuit being connected between said conversion means and said laser diode and provided with first voltage comparator means adapted to produce a laser-diode d.c. bias voltage corresponding to the mean value of the optical output power produced by said laser diode;
• a second circuit for stabilizing the amplitude of modulation of the optical output power produced by said laser diode, said circuit being connected between said conversion means and said laser diode and provided with means for detecting the peak-to-peak amplitude of the laser-diode modulating signal and means for differentiating the signals generated by said peak-to-peak detection means so as to deliver a laser-diode modulating signal having a stabilized peak-to-peak amplitude corresponding to the difference between the maximum optical output power and the minimum optical output power produced by the laser diode,
• wherein said first circuit for stabilizing the mean value of the optical output power produced by the laser diode is further provided with means for restituting the low-frequency component of the signal to be transmitted, said restituting means being connected between the output of said peak-to-peak detection means and the input of said first voltage comparator means, thus permitting stabilization of the minimum and maximum values of optical output power produced by said laser diode.