Optical signal transmitter

An optical signal transmitter comprising:

• a semiconductor laser diode;
• a driver circuit operatively connected to the semiconductor laser diode for supplying a bias current and a pulse current corresponding to the level of an input signal to the semiconductor laser diode;
• a waveform forming circuit provided at an input side and supplied with the input signal for forming the input signal to have 100% duty;
• a bias current controller operatively connected to the driver circuit for controlling the level of the bias current;
• and
• a pulse current controller operatively connected to the driver circuit including a temperature sensitive element and for controlling the level of the pulse current in a direction opposite to a temperature fluctuation in an optical output of the semiconductor laser diode.

An optical signal transmitter comprising:

• a semiconductor laser diode;
• a driver circuit operatively connected to the semiconductor laser diode for supplying a bias current and a pulse current corresponding to the level of an input signal to the semiconductor laser diode;
• a waveform forming circuit provided at an input side and supplied with the input signal for forming the input signal to have 100% duty;
• a bias current controller operatively connected to the driver circuit including a temperature sensitive element and for controlling the level of the bias current in a direction opposite to a temperature fluctuation in an optical output of the semiconductor laser diode;
• and
• a pulse current controller operatively connected to the driver circuit for controlling the level of the pulse current.

An optical signal transmitter comprising:

• a semiconductor laser diode;
• a driver circuit operatively connected to the semiconductor laser diode for supplying a bias current and a pulse current corresponding to the level of an input signal to the semiconductor laser diode;
• a waveform forming circuit provided at an input side and supplied with the input signal for forming the input signal to have 100% duty;
• a bias current controller operatively connected to the driver circuit including a temperature sensitive element and for controlling the level of the bias current in a direction opposite to a temperature fluctuation in an optical output of the semiconductor laser diode;
• and
• a pulse current controller operatively connected to the driver circuit including a temperature sensitive element and for controlling the level of the pulse current in a direction opposite to a temperature fluctuation in an optical output of the semiconductor laser diode operatively connected to the driver circuit for controlling the level of the pulse current.

An initial value adjustment device for use in an optical signal transmitter including a semiconductor laser diode, a driver circuit operatively connected to the semiconductor laser diode for supplying a bias current and a pulse current corresponding to the level of an input signal to the semiconductor laser diode, a bias current controller operatively connected to the driver circuit for controlling the level of the bias current, a pulse current controller operatively connected to the driver circuit for controlling the level of the pulse current, and a duty variable circuit operatively connected to the driver circuit for setting the duty of the the input signal to make the duty of an optical output from the semiconductor laser diode more than 100% at an initial adjustment, the initial value adjustment circuit comprising:

• a signal generator for generating the optical input signal;
• a optical power meter for monitoring an optical output of the optical signal transmitter;
• a variable voltage source for setting initial values of the bias current, the pulse current and the duty of the optical output;
• and
• a CPU for monitoring an output of the optical power meter and controlling the value of the output of the signal generator and the variable voltage source to set the initial values by adjusting the voltage of the variable voltage source so that the value of the optical power meter becomes a desired value when the output signal of the signal generator are changed to a plurality of mark ratios.