Photonic Crystal Fiber And Applied Research

The transfer properties of the electron can not compare with that of photon. To solve the problem of "electron bottleneck" in the communication systems, photonic crystal quickly becomes the research pivot. The prime property of photonic crystal exists in the gaps, which could prohibit the propagation of electromagnetic wave within a certain range of frequencies, so it can control the light transmission in the medium The photonic crystal fibers(PCFs) are a new kind of optical fibers that employ the structured arrangement of the photonic crystals(PC).Different from the traditional fiber, photonic crystal fiber (PCF) guides wave through two different mechanisms: one is the same as traditional fiber; the other guides wave through photonic band gap(PBG) effect. Light can not propagate in PCF if its frequency falls into the band gap. PCF have been of great interest in recent years, mainly because of their novel optical characteristics, such as endlessly single mode, flatten dispersion, large mode area and high non-linear. The further research of PCF will take the important role for the development of telecommunication.Based on a scalar approximation, the waveguide mode and dispersion property of PCFs are investigated with an effective index approach in this paper. It is found that PCFs can be single-mode over a very broad spectral range by changing PCFs cladding air-filling fraction or pitch of holes or core diameter. PCFs can support single mode operation in a large wavelength range, the zero dispersion wavelength can be shifted by adjusting the structure parameters. PCF with large air holes and its applications in dispersion compensation are also discussed. PCF can guide light well in its core. Further more the mode area of PCF can be easily adjusted.At last, the coupling property of twin-core photonic crystal fiber is simulated in computer with beam propagation method. The variety rules of coupling-length with both wavelength and air holes have been found, and this provide some guide for the fabrication of plastic twin-core photonic crystal fiber.