Optical transmitter

An optical transmitter (1) for a communications system comprising:

• A) a laser (2) generating a carrier that is directly modulated by an energy dispersing signal (V);
• B) an optical intensity modulator (3) for receipt of the modulated carrier (2b, 3a) and for receipt of an intelligence signal (N), said optical intensity modulator indirectly modulating said modulated carrier with the intelligence signal (N);
• C) a splitter (10) having an input connected to the intelligence signal (N), and also having first and second splitter outputs, the first splitter output for connection to the optical intensity modulator (3);
• and
• D) a pre-distortion circuit (6) for receipt of the second splitter output, for converting the intelligence signal (N) into the energy-dispersing signal (V), which is a signal derived from the intelligence signal (N) and further so that the energy-dispersing signal (V) serves to compensate for the non-linearity of the optical intensity modulator (3).

An optical transmitter (1) for a communications system comprising:

• A) a laser (2) generating a carrier that is directly modulated by an energy dispersing signal (V);
• B) an optical intensity modulator (3) for receipt of the modulated carrier (2b, 3a) and for receipt of an intelligence signal (N), said optical intensity modulator indirectly modulating said modulated carrier with the intelligence signal;
• C) a first pre-distortion circuit (7) to compensate for amplitude modulation of the laser output caused by direct modulation of the laser by the energy-dispersing signal (V), wherein the output of the first predistortion circuit (7) is combined with the intelligence signal (N);
• and
• D) a second pre-distortion circuit (8) connected to the output of the first pre-distortion circuit (7) and to the intelligence signal (N) for compensating for additional non-linearities of the optical transmitter.