高频CO_2激光脉冲写入长周期光纤光栅的方法

A Technique Fabricating Long Period Fiber Gratings by High-Frequency CO_2 Laser Pluses

在国际上首次提出了高频CO2 激光脉冲写入长周期光纤光栅的方法 .该方法与低频CO2 激光脉冲写入法或紫外光等其它写入法相比具有许多独特的优点———效率高、成本低 ,重复曝光容易、激光加热区域的周期性变化通过扫描振镜的偏振来实现而光纤固定不动 ,因此特别适合于研制具有特殊用途的新型LPFG .详细分析了单侧CO2激光入射导致LPFG横截面折射率分布不均匀的形成机理并提出了降低LPFG双折射的方法 .

A technique fabricating long period fiber gratings (LPFGs) by high-frequency CO_2 laser pulses is proposed and demonstrated,for the first time,to our knowledge.In comparison with other fabrication techniques of LPFG,such as using low-frequency CO_2 laser and UV laser,such a technique has many unique advantages,including high efficiency,low cost,low insert loss,and repetitive exposal being easy.Exposing area of the fiber is transferred periodically by means of the scan lens turning.Then,it is especially propitious to developing novel LPFGs using the fabrication technique.It is analyzed that the single side incident CO_2 laser resulted in an asymmetric refractive-index distribution,within the cross-section of the LPFG.