A few-mode microstructured optical fiber is designed for low bending loss applications. Low-index rods and air-holes are applied to lower the splicing loss with the standard single-mode optical fiber (SMF) and to achieve ultra-low bending loss. Numerical results show that the proposed fiber can realize low bending loss of 0.004 dB/turn at the bending radius of 5 mm and low splicing of 0.04 dB with the standard SMF.
Based on the coupled-mode theory, Cherenkov second harmonic generation (CSHG) from a channel waveguide has been analyzed and discussed in detail. The conversion efficiency with only conversion depletion and the conversion efficiency with conversion depletion and propagation loss are obtained respectively, the results show that for the case of low conversion efficiency the conversion depletion can be neglected, but for the case of high conversion efficiency we must take conversion depletion into account, and the propagation loss must be taken into accounted for the both. Furthermore, the nonlinear phase shift (NPS) of the fundamental beam can be maximized by choosing appropriate grating period and appropriate waveguide thickness, which makes the configuration have a promising potential to realize all-optical switches.
In an earlier approach, the 2-D acoustical field profiles on the substrate region are often calculated with BPM. In this
paper, we present a new approach based on the finite element - artificial transmitting boundary method and calculate the
2-D acoustical field on the substrate region.