Single-Mode Light Generation in DFB Fiber Laser: Wavelength-Scale Electromagnetic Modelling by the Method of Single Expression

Distributed feedback (DFB) semiconductor and fiber lasers are widely used in different areas of science, technology, medicine, etc. Till now stable single-mode radiating fiber lasers operating in ultraviolet, visible and infrared bands are under strong demand. Single-mode operation of fiber lasers is very advantageous for telecommunication, spectroscopy, sensors applications, etc. However, there is a lack of a wavelength-scale electromagnetic analysis of such fiber lasers at the single-mode radiation. In the current work the results of correct wavelength-scale electromagnetic analysis of radiation of DFB fiber lasers are presented. For wavelength-scale analysis the non-traditional method of single expression is used. In accordance with the known information, single-mode radiation from DFB fiber laser is observed at the pi-shift in the middle of permittivity sinusoidal modulation of an amplifying fiber. Numerically obtained wavelength-scale distributions of electric field component and power flow density within the DFB amplifying fiber will be useful in designing single-mode radiating DFB fiber lasers.