The Study Of Gain Distribution And Output Characteristics Of DPLs With Different Pumping Structures

The Diode Pumped solid state Laser (DPL) has solid-state, small size, long service life, high pumping efficiency and other advantages. Therefore, it has extensive application and broad prospect in laser communication, remote sensing detection, medical, industry, military and defense fields, and it has attracted great attention from researchers. The paper studies the gain distribution and output characteristics of different DPLs with different pumping structures, analyzes the characteristics of pumping light and pumping structure under different pumping conditions, and uses numerical calculation method to calculate the influences of pumping light parameter on the gain distribution of laser working crystal under different pumping conditions. Calculation results indicate that the smaller the pumping beam waist radius is, the greater the gain of the laser crystal on the axis, the radial gain in perpendicular direction of axis is more concentrated; the smaller the absorption coefficient of crystal is, the greater the pumping uniformity is, but the total absorption efficiency decreases; when the absorption coefficient and waist radius are too small,the crystal cannot completely absorb the energy of the pumping light, the pumping light utilization will be reduced; if the reflection enhancing coating of pumping light is increased on the lateral pumping light emitting surface of crystal at this time, this can improve the energy utilization efficiency of the pumping light. Then, numerical calculation is adopted to measure the beam waist size of different pumping lights, as well as the influence of beam waist position on the output characteristic of laser. The smaller thebeam waist radius of pumping light is, the better the output characteristic of laser. Especially for end surface pumping structure, the optimum beam waist position of pumping light will bring out the best output characteristic of laser. Finally, the paper carries out an experimental study of the output power characteristics and spectral characteristics of fiber coupled LD by studying theend surface pumping structure, and further makes a comparative study on the output power and output beam quality of end surface off-axis pumped laser.