Semiconductor Laser with External Optical Feedback in Stationary Mode

The spectrum mode and spatial undulations power of multimode semiconductor lasers with a change in the external optical feedback were studied. The spectra of the longitudinal modes of the solitary laser and laser with external optical feedback (OFB) at various deficit amplification dominant modes and different distances to the outer reflector were calculated. AS Shown, the decrease in the gain spectrum of the laser attenuation approaches the single mode. In a laser with OFB spectral envelope got complicated. In this case, the status of the dominant model may change. including non-adjacent. By reducing deficit of gain, the number of modes in spectrum decreased, as in the case of solitary laser. The results should be taken into consideration when constructing autodyne displacement sensors based on multimode semiconductor lasers. The considered model and numerical estimation considered can be used to optimize the conditions of external OFB in such systems, to maximize the sensor response to the back-reflected radiation.