Wang Yiping, Bartelt Hartmut, Becker Martin, Brueckner Sven, Bergmann Joachim, Kobelke Jens, Rothhardt Manfred
Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany.
Appl Opt. 2009 Apr 10;48(11):1963-8. doi: 10.1364/ao.48.001963.
We report on fiber Bragg gratings (FBGs) inscribed in pure-silica and Ge-doped photonic crystal fibers (PCFs) with a two-beam interference technique and a femtosecond or excimer laser. Such a technique enables the inscription of FBGs for different Bragg wavelengths with high flexibility. Effects of H(2)-loading and Ge doping on the efficiency of grating inscription were investigated by measuring the development of Bragg wavelength and attenuation in the transmission spectra with an increased exposure dose. H(2)-loading dramatically enhances the laser-induced index modulation not only in Ge-doped PCFs but also in pure-silica PCFs. We observed a reversible Bragg wavelength shift during femtosecond pulse irradiation, which indicates an internal temperature rise of approximately 77 degrees C.
我们报道了利用双光束干涉技术以及飞秒或准分子激光在纯硅和掺锗光子晶体光纤（PCF）中写入光纤布拉格光栅（FBG）的情况。这种技术能够以高灵活性写入不同布拉格波长的FBG。通过测量随着曝光剂量增加透射光谱中布拉格波长的变化和衰减，研究了氢气加载和锗掺杂对光栅写入效率的影响。氢气加载不仅显著增强了掺锗PCF中激光诱导的折射率调制，在纯硅PCF中也是如此。我们在飞秒脉冲辐照期间观察到了可逆的布拉格波长偏移，这表明内部温度升高了约77摄氏度。
