.980 Nm, Filter And Write In The New Bending Fiber-optic Long-period Fiber Grating,

Fiber grating, being one of the crucial devices, has developed into many applications in optical communication and sensing. Be all-fiber components, they have the advantages of low insertion loss, high return loss or extinction and low cost. What's more, in the fabrication progress, we can achieve sophisticated spectral characteristics through choosing a suitable fabrication method and the control of the parameters of the gratings. Since it was fabricated in the 1990s, long-period fiber grating, having well spectral complementary with fiber Bragg grating, attracts more and more attention now.Along with the rapid development of social and economic, the requirement of high speed communication increased quickly. As critical devices of long-distance optical communication, the work bandwidth of erbium-doped fiber amplifiers (EDFAs) must also increase to meet the requirements. Therefore, the new ultra-wideband EDFAs are desirable. In EDFAs, a wavelength-division-multiplexer (WDM) will set in to filter out the remained pump so that it can eliminate the influence of communication. The suppression at 980nm waves of the commercial 980/C+L-band WDM is limited, usually no more than 20dB.In this dissertation, to filter out the pump at 980nm waves better, we first put forward and fabricated a new kind of long-period fiber grating filter. The grating was written in the commercial germanium-boron co-doped single-mode fiber by high frequency CO2 laser. In the fabrication progress, by adjustment and optimization of the grating parameters and the parameters of the CO2 laser, we get a well grating as needed, the suppression of the grating at 980nm waves is about 26dB, the loss of it in C+L-band is less than 0.8dB and it is flat so that it can cascade with the commercial gain flatten filters of EDFAs, the polarization dependent loss(PDL) of it is less than O.1dB, what's more, the filter has a very good thermal stability. The fabrication of this long-period fiber grating provides a direction for further optimize and improve the performance of the filter laid a foundation.With the development of optical communication, the study on fiber, the basic transmission medium of optical communication, increased gradually. In 2009, Corning released a new kind of bend-insensitive single-mode fiber, which can meet the FTTH's requirements well. Compared with the common fiber, this fiber has a nano-engineered ring, which is 8-14μm aside of the core, with a thickness of 2-10μm. Compared with the previous bend-insensitive fiber, it has a better compatibility with ordinary single-mode optical fiber, and the splicing loss of them is low.For the special structure of the fiber, we have written long-period fiber gratings in it, the temperature and strain sensitivity also were measured, something special had observed. We analyzed the transmission spectrum of the grating written in the fiber, and explained the new phenomenon, this work provided the basis and reference for further study on the long-period fiber gratings written in this fiber.