中文摘要：

利用光纤延时自外差法对单块非平面Er：YAG环形振荡器（NPRO）输出单纵模激光的短期频率稳定度进行了测量。激光器输出波长为1645nm。测量了延时时间分别为0、25μs，0.75μs，1．25μs，1．75μs，2．25μs，2．75μs，5．25μs，7．25μs，9．75μs．108．5μs，166μs的输出激光的自外差拍频信号。设置频谱仪的span为20kHz，扫描时间为10s，ResBW为51Hz，VBW为1Hz，测量拍频信号的3dB带宽。在延时时间0．25～9．75Izs范围内，通过线性拟合在不同延时下的3dB带宽，得到单纵模NPRO激光器的短期频率稳定度为201Hz／μs。光纤延时长度为21．7km和33．2km时，测量的3dB带宽约为14kHz．

英文摘要：

Using the fiber delayed self-heterodyne method, the short-term frequency stability of the monolithic nonpla- nar Er ： YAG ring oscillator（NPRO） outputting the single longitudinal-mode was measured. The laser output wave- length is 1645nm. The self-heterodyne beat signal of the laser was achieved under different delay time about 0.25 μs, 0. 75 μs, 1.25 μs, 1.75 μs,2. 25 μs,2. 75 μs,5.25 μs,7.25 μs,9. 75 μs, 108.5 μs, 166 μs. When span of the spectrum analyzer is 20 kHz,sweep time is 10 s,Res BW is 51 Hz and VBW is 1Hz,the 3 dB bandwidth of the beat signal was measured. In the delay time range of 0. 25 - 9. 75 μs, through linear fitting of the 3 dB bandwidth under different delay time,the short-term frequency stability of the single longitudinal-mode NPRO laser is 201 Hz/μs. In addition,the 3 dB bandwidth of about 14 kHz was obtained when the lengths of the delay time fiber are about 21.7 km and 33.2 km.