Maji Partha Sona, Roy Chaudhuri Partha
Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302, India.
Int Sch Res Notices. 2014 Dec 31;2014:276082. doi: 10.1155/2014/276082. eCollection 2014.
In this work, a new design of ultraflat dispersion PCF based on square-lattice geometry with all uniform air holes towards broadband smooth SCG around the C-band of wavelength has been presented. The air hole of the inner ring was infiltrated with liquid of certain refractive indices. Numerical investigations establish a near zero ultraflattened dispersion of 0 ± 0.78 ps/nm/km in a wavelength range of 1496 nm to 2174 nm (678 nm bandwidth) covering most of the communications bands with the first zero dispersion wavelength around 1.54 μm. With the optimized ultraflattened fiber, we have achieved a broadband SC spectrum with FWHM of 350 nm with the central wavelength of 1550 nm with less than a meter long of the fiber by using a picosecond pulse laser. We have also analyzed the sensitivity of the optimized dispersion design by small variations from the optimum value of the geometrical structural parameters. Our investigations establish that for a negative change of PCF parameters, the profile retains the smooth and flat SCG spectra; however, for a positive change, the smooth and a flat spectrum is lost. The new design of the fiber will be capable of covering huge diverse field of DWDM sources, spectroscopy, meteorology, optical coherence tomography, and optical sensing.
在这项工作中，提出了一种基于方形晶格结构的超扁平色散光子晶体光纤的新设计，其所有空气孔均均匀，旨在实现围绕波长C波段的宽带平滑超连续谱产生（SCG）。内环的空气孔被注入具有特定折射率的液体。数值研究表明，在1496 nm至2174 nm（678 nm带宽）的波长范围内，超扁平色散接近零，为0±0.78 ps/nm/km，覆盖了大部分通信波段，第一个零色散波长约为1.54μm。利用优化后的超扁平光纤，通过使用皮秒脉冲激光器，我们在光纤长度小于一米的情况下，实现了中心波长为1550 nm、半高宽为350 nm的宽带超连续谱。我们还分析了几何结构参数的最佳值有小的变化时，优化色散设计的灵敏度。我们的研究表明，对于光子晶体光纤参数的负向变化，光谱轮廓保持平滑和扁平的超连续谱；然而，对于正向变化，平滑和扁平的光谱会消失。这种新型光纤设计将能够覆盖密集波分复用（DWDM）光源、光谱学、气象学、光学相干断层扫描和光学传感等众多不同领域。
