780373.fig.007
Figure 7: The RF spectrum of the O/E converted laser output by a fast photo detector. The 3-dB linewidth is less than 1 MHz. The inset shows the full span spectrum. There is no spurious low-frequency spectral noise that is characteristic to irregular self-pulsation. The device under test here is a 1 mm long 6-MQW active layer device [14].