Using the optical feedback regime for evaluating the slope of the modulation characteristic of a semiconductor laser

A new simple method based on the optical feedback phenomena is proposed for evaluating the slope of the modulation characteristic (generation frequency versus injection current) of a semiconductor laser. The slope is determined using the frequency of a signal formed as a result of the interference between the initial and scattered radiation, which is measured at the output of a photodiode built into the laser. The proposed method is theoretically justified, the scheme of realization is described, and the results of experimental verification using a particular laser diode are presented.