CAJ | 학술논문

增益光纤的折射率和离子掺杂分布是决定光纤激光器输出功率和光束质量的重要因素，针对大模场光纤弯曲效应对模场面积和模场畸变的影响进行了数值分析，采用有限元方法计算了不同折射率和掺杂离子分布光纤的模场面积和增益系数。提出了高斯复合型折射率和掺杂离子分布的大模场增益光纤结构，该结构可有效提高增益光纤的增益系数和高阶模抑制系数，并具有较强的抗弯曲特性，较好的平衡了模场面积与抗弯曲特性的矛盾。根据计算结果设计了直径为65μm的高斯复合型折射率和掺杂分布的增益光纤，在波长为1.064μm的条件下，基模有效模面积达到1.17×103μm2，基模相对增益系数和高阶模相对抑制系数分别达到0.58和0.2088，有效地提高了光纤激光器和放大器的输出光束质量。
증익광섬적절사솔화리자참잡분포시결정광섬격광기수출공솔화광속질량적중요인소，침대대모장광섬만곡효응대모장면적화모장기변적영향진행료수치분석，채용유한원방법계산료불동절사솔화참잡리자분포광섬적모장면적화증익계수。제출료고사복합형절사솔화참잡리자분포적대모장증익광섬결구，해결구가유효제고증익광섬적증익계수화고계모억제계수，병구유교강적항만곡특성，교호적평형료모장면적여항만곡특성적모순。근거계산결과설계료직경위65μm적고사복합형절사솔화참잡분포적증익광섬，재파장위1.064μm적조건하，기모유효모면적체도1.17×103μm2，기모상대증익계수화고계모상대억제계수분별체도0.58화0.2088，유효지제고료광섬격광기화방대기적수출광속질량。
The gain fiber is the important indicators to determine the output power and beam quality of fiber laser. The paper focused on the large-mode-area fiber (LMA) bending effect on fundamental mode (FM) area and mode field distortion by numerical analysis, the FM area and gain coefficient of LMA fiber with different refractive index (RI) and doped distributions were solved by finite-element method. The Gaussian hybrid refractive index distribution and doping profile were proposed firstly. It can effectively improve the gain coefficient and suppression coefficient of high-order modes (HOMs). Moreover, the bending against of the fiber can be strengthen, the design can balance the contradiction the mode area and bending resistance. Based on the numerical calculation, the gain fiber with Gaussian hybrid RI distribution and doping profile were designed, the fiber diameter was 65μm. At the wavelength of 1.064μm, the FM area can be 1.17×103μm2, the FM relative gain coefficient and relative suppressing coefficient can reach 0.58 and 0.208 8, the output and beam quality of the fiber laser can be improved effectively.