Hi-bi-nlcfbg and hi-bi-ufbg used to compensate all-orders pmd

摘要

The first- and second- and third-order polarization mode dispersion has become a critical issue for high-data-rate optical systems. This paper advance a two-stages PMD compensator, which are made of a long length of Hi-Bi-NLCFBG(high-birefringence nonlinearly chirped fiber Bragg gratings) and a short length of Hi-Bi-U FBG(high-birefringence uniform fiber Bragg gratings). The first stage adopts a Hi-Bi-NLCFBG[1], which been used compensated the first- and second-orders PMD, and the second-stage adopts a Hi-Bi-UFBG, which used for third-order PMD compensation, respectively. Based on the numerical simulations, the spectrum characteristics and time delay of Hi-Bi-NLCFBG is investigated, then, we put forward that the amount of compensated PMD is proportion to length of Hi-Bi-NLCFBG, double-mode refraction index difference of highly birefringence fiber for the first time. Also, we modify a formula aiming to former literature; It is suggested that the value of first-chirped coefficient of Hi-Bi-NLCFBG must be suitable, or else, the effect of compensated PMD is bad. Subsequently, the differential group delay (DGD) of NLCFBG of normal polarization-mode of the single-polarization fiber is analyzed by means of numerical simulation, and we also analyzed the PMD of NLCFBG UV-writing leak-mode of the SP-SMF (Single Polarization Single Mode Fiber) In order to compensated the third-order PMD, we investigate the out-of-band time-delay of UFBG on the SP-SMF at the end of this paper.