A novel photonic crystal fiber (PCF) based on pure silica is designed to transmit 114 orbital angular momentum (OAM) modes in the wavelength range of 1.2 μm–1.8 μm. The PCF composed of a central round air-hole, ring-shaped core, and air-hole array ensures effective refractive index differences of the constituent vector modes above 10−4 and stable transmission of the OAM modes. The finite element method is implemented to analyze the PCF. The confinement losses and nonlinear coefficients of all the eigenmodes at 1550 nm are less than 3.03 × 10−7 dB m−1 and 1.30 w−1 km−1, respectively. In addition, the PCF shows higher effective refractive index difference, lower confinement loss, and nonlinear coefficient thus holding large promise in high-performance fiber communication systems.

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Extensive cytological and histological research, correlated with physiological experimental analysis, have been done on the anterior pituitaries of many different vertebrates which have provided the knowledge to create the concept that specific cell types synthesize, store and release their specific hormones. These hormones are stored in or associated with granules. Nevertheless, there are still many doubts - that need further studies, specially on the ultrastructure and physiology of these endocrine cells during the process of synthesis, transport and secretion, whereas some new methods may provide the information about the intracellular structure and activity in detail.In the present work, ultrastructural study of the hormone-secretory cells of chicken pituitaries have been done by using TEM as well as HR-SEM, to correlate the informations obtained from 2-dimensional TEM micrography with the 3-dimensional SEM topographic images, which have a continous surface with larger depth of field that - offers the adventage to interpretate some intracellular structures which were not possible to see using TEM.