Characterization of Fabricated Photonic Crystal Fibers Using Effective Index Method

In this paper, the characteristics of photonic crystal fibers (PCFs), which have been experimentally determined in the last few years in Iran's Telecom Research Center are analyzed and compared theoretically using an effective index method. The PCFs under investigation are fabricated with a high speed drawing process that has not yet been reported elsewhere. It was shown that at higher wavelengths in PCFs; the light field is confined in the core where in shorter wavelengths the field spreads into the cladding region. This phenomenon leads to affect the numerical aperture and the normalized frequency of the PCFs, because these two parameters directly depend on the diameter of the air-hole and the spacing between them in the cladding region. The measured results show that the PCF fabricated at high drawing speeds has a loss of 12 dB/km of speed, which is a reasonable level compared to other published reports. In addition, we have shown that a lower spacing between the adjacent air-holes would reduce the loss in the PCFs.