Relative intensity noise of a continuous-wave interband cascade laser at room temperature.

This Letter investigates the relative intensity noise (RIN) characteristics of a continuous-wave 3.4 µm interband cascade laser operated at room temperature. The RIN decreases with an increasing pump current and reaches down to -130 dB/Hz at a frequency of 450 MHz. In addition, it is proved that the current noise of the laser pump source dominates the RIN for frequencies below 100 MHz. The measured RIN is quantitatively in agreement with the theoretical analysis, from which the gain coefficient and the transparent carrier number of the laser are extracted.