Laser Diode Modulation Under Large Signal Conditions

Large signal behavior of the Laser Diode is analyzed with the aim of finding a qualitative relationship between modulation amplitude and the change in the shape of its transferfunction. It is found that, at quasi-static conditions, increasing the amplitude of the modulating signal smoothes out the originalpiecewise-linear transfer function of the diode. It further shifts the – now smoothed – knee point to lower DC currents. As the frequency increases, however, these effects become less and lesspronounced. In addition, the transfer function becomes rather wavy due to the failure of current density to reach the saturationlevel necessary for adequate stimulated emission. At even higher frequencies, carrier density never accumulates in response toshort pulses of current. In these conditions the transfer function reverts back to its original shape.

Keywords:

component , Laser Diode , modulation , large signal , transfer function