Zhu L, Verhoef A J, Jespersen K G, Kalashnikov V L, Grüner-Nielsen L, Lorenc D, Baltuška A, Fernández A
Photonics Institute, Vienna University of Technology, Gusshausstrasse 27/387, 1040 Vienna, Austria.
Opt Express. 2013 Jul 15;21(14):16255-62. doi: 10.1364/OE.21.016255.
Fiber oscillators operating in the normal dispersion regime allow generating high energy output pulses. The best stability of such oscillators is observed when the intracavity dispersion is close to zero. Intracavity dispersion compensation in such oscillators can be achieved using a higher-order mode fiber, which substantially reduces the higher order dispersion compared to all-normal dispersion oscillators or oscillators using intracavity gratings for dispersion compensation. Using this approach, we are able to obtain relatively high energy pulses, with high fidelity. Our modeling based on an analytic approach for oscillators operating in the normal dispersion regime predicts that at intermediate pulse energies an almost flat chirp can be obtained at the oscillator output enabling good pulse compression with a grating compressor close to Fourier limited duration. Here, we present a mode-locked ytterbium-doped fiber oscillator with a higher-order mode fiber operating in the net normal-dispersion regime, delivering 7.2 nJ pulses that can be dechirped down to 62 fs using a simple grating compressor.
工作在正常色散区域的光纤振荡器能够产生高能量输出脉冲。当腔内色散接近零时，可观察到此类振荡器的最佳稳定性。在此类振荡器中，腔内色散补偿可通过使用高阶模光纤来实现，与全正色散振荡器或使用腔内光栅进行色散补偿的振荡器相比，高阶模光纤可大幅降低高阶色散。采用这种方法，我们能够获得具有高保真度的相对高能量脉冲。我们基于对工作在正常色散区域的振荡器的解析方法进行的建模预测，在中等脉冲能量下，振荡器输出端可获得几乎平坦的啁啾，从而能够使用接近傅里叶极限持续时间的光栅压缩器实现良好的脉冲压缩。在此，我们展示了一种锁模掺镱光纤振荡器，其采用高阶模光纤工作在净正常色散区域，输出7.2 nJ的脉冲，使用简单的光栅压缩器可将其啁啾消除至62 fs。
