飞秒激光脉冲在大气中的色散及补偿  

Dispersion and compensation of femtosecond laser pulses in the atmosphere

作　　者：沈振民[1] 刘红影[1] 蓝天[1] 李少辉[2] 倪国强[1] 刘浩杰[1] 

机构地区：[1]北京理工大学光电成像技术与系统教育部重点实验室,北京100081 [2]中国空间技术研究院,北京100094

出　　处：《红外与激光工程》2013年第4期940-946,共7页Infrared and Laser Engineering

基　　金：中国科学院光电研究院"雏鹰计划"

摘　　要：卫星飞秒激光测距理论上可达到亚微米量级的测距精度,但飞秒激光脉冲在大气中传输时由色散导致的脉冲展宽显著,会使测距精度下降。为补偿飞秒激光脉冲在大气中的色散需对其色散量进行定量计算。推导了飞秒激光脉冲在大气中的群速度色散和脉冲展宽公式,表明脉冲展宽程度和群速度色散及传输距离有关;中心波长相同的飞秒激光脉冲脉宽越窄色散越严重,而当脉宽相同时,中心波长越短色散越严重。计算比较了大气和BK7玻璃的群延时、群速度色散和三阶色散。卫星激光测距系统应采用中心波长较长的1 550 nm的飞秒激光脉冲,脉宽应适当选取。由于飞秒激光色散严重,提出了采用单模光纤序列进行粗补偿和采用光栅对进行精密补偿的两种补偿相结合的方式对其色散进行补偿。Satellite femtosecond laser ranging can theoretically achieve the ranging accuracy in the order of submicron, but femtosecond laser pulse duration broadening caused by the dispersion when it propagates in the atmosphere significantly makes the ranging accuracy decreased. To compensate the dispersion, the dispersion amount of femtosecond laser was calculated in the atmosphere. The group velocity dispersion formula and pulse duration broadening formula of femtosecond laser pluses in the atmosphere were derived. The results show that laser pulse broadening is determined by the group velocity dispersion and the propagation distance. Also shows that the dispersion is much larger when the pulse duration is much smaller under the same center wavelength, and the dispersion is much larger when the center wavelength is much smaller under the same pulse duration. Calculate the group delay, the group velocity dispersion and the three order dispersion in the atmosphere and BK7. The satellite femtosecond laser ranging system should adopt femtosecond laser with a longer center wavelength of 1 550 nm, and the pulse duration should be properly selected. Because femtosecond laser pulses have large dispersion when it transfers in the atmosphere, the dispersion compensation method is given by using single mode fiber sequence for the coarse compensation and grating pairs for the fine compensation

关 键 词：飞秒激光测距 脉冲展宽 群速度色散 色散补偿 

分 类 号：TN249[电子电信—物理电子学]