40GHz皮秒光脉冲序列光谱展宽的实验研究

实验采用具有较大正常色散值的高非线性光纤（HNLF），应用脉冲啁啾补偿压缩技术的改进方案实现了40GHz、1．2ps光脉冲序列光谱的更大展宽。在该方案中，脉冲首先通过一定长度的HNLF，成为光谱展宽的线性正啁啾脉冲；然后经过相应长度的普通单模光纤（SMF）进行啁啾补偿压缩以重新提高峰值功率；最后进人第2段HNLF实现脉冲光谱的进一步展宽。实验结果表明，在使用相同长度HNLF（150m）和相同抽运脉冲输入条件下，改进方案10dB带宽增加了3．28nm，并且相干特性保持良好。实验表明，对于40GHz皮秒光脉冲序列，在其峰值功率受自身高重复频率限制不能被光功率放大器充分放大的情况下，该方案是实现脉冲光谱在此类HNLF中展宽的有效途径。

Experimental Investigation of Optical Spectrum Broadening of 40 GHz Pico Second Pulse Train

Utilization of highly nonlinear fiber(HNLF) with relative large normal dispersion in which an improved scheme that applies the pulse chirp compensation technique is presented to further broaden optical spectrum of 40 GHz,1.2 ps optical pulse train is experimentally realized.In the scheme,the pulse is launched into the HNLF of the first section to generate the spectrum-broadened linearly up-chirped pulse,and re-compressed after propagating through a suitable length of conventional single-mode fiber(SMF) of the second section for the pulse chipr being compensated.At last,the pulse travels through the second HNLF for further optical spectrum broadening.The experimental results shows that the 3.28 nm increment of 10 dB spectrum bandwidth is obtained when the new scheme is implemented given the same HNLF length and input seed pluses,and the coherence properties of the original pulses are maintained.For 40 GHz pico second pulse train,the experiment confirms that this scheme provides an effecive means of pulse spectrum broadening in the HNLF when the peak power of seed pulse is confined by the EDFA output power and the high repetition rate of pulse laser.