Preface
Acknowledgements
Introduction
1 Basics of photonic crystal fibers
1.1 From conventional optical fibers to PCFs
1.2 Guiding mechanism
1.2.1 Modified totalinternal reflection
1.2.2 Photonic bandgap guidance
1.3 Properties and applications
1.3.1 Solid-core fibers
1.3.2 Hollow-core fibers
1.4 Loss mechanisms
1.4.1 Intrinsic loss
1.4.2 Confinement loss
1.4.3 Bending loss
1.5 Fabrication process
1,5.1 Stack-and-draw technique
1.5.2 Extrusion fabrication process
1.5.3 Microstructured polymer optical fibers
1.5.4 OmniGuide fibers
1.6 Photonic crystal fibers in the market
Bibliography

2 Guiding properties
2.1 Square-lattice PCFs
2.1.1 Guidance
2.1.2 Cuto:ff
2.2Cutoff of large-mode area triangular PCFs
2.3 Hollow-core-modified honeycomb PCFs
2.3.1 Guidance andleakage
2.3.2 Birefringence
Bibliography

3 Dispersion properties
3.1 PCFs for dispersion compensation
3.2 Dispersion of square-lattice PCFs
3.3 Dispersion-fl.attened triangular PCFs
3.3.1 PCFs with modified air-hole rings
3.3.2 Triangular-core PCFs
Bibliography

4 Nonlinear properties
4.1 Supercontinuum generation
4.1.1 Physics of supercontinuum generation
4.1.2 Highly nonlinear PCFs
4.1.3 Dispersion properties and pump wavelength
4.1.4 Infiuence of the pump pulse regime
4.1.5 Applications
4.2 Optical parametric amplification
4.2.1 Triangular PCFs for OPA
4.2.2 Phase-matching condition in triangular PCFs
4.3 Nonlinear coefficient in hollow-core PCFs
Bibliography

5 Raman properties
5.1 Raman effective area and Raman gain coefficient
5.2 Raman properties of triangular PCFs
5.2.1 Silica triangular PCFs
5.2.2 Tellurite triangular PCFs
5.2.3 Enlarging air-hole triangular PCFs
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6 Erbium-doped fiber amplifiers
A Finite Element Method

精彩書摘

　　1.3.1 Solid-core fibers
　　Index-guiding PCFs， with a solid glass region within a lattice of air-holes， offer a lot of new opportunities， not only for applications related to fundamental fiber optics. These opportunities are related to some special properties of the photonic crystal cladding， which are due to the large refractive index contrast and the two-dimensional nature of the microstructure， thus affecting the birefringence， the dispersion， the smallest attainable core size， the number of guided modes and the numerical aperture and the birefringence. Highly birefringent fibers Birefringent fibers， where the two orthogonally polarized modes carried in a single-mode fiber propagate at different rates， are used to maintain polarization states in optical devices and subsystems. The guided modes become birefringent if the core microstructure is deliberately made twofold symmetric， for example， by introducing capillaries with different wall thicknesses above and below the core. By slightly changing the air-hole geometry， it is possible to produce levels of birefringence that exceed the performance of conventional birefringent fiber by an order of magnitude. It is important to underline that， unlike traditional polarization maintaining fibers， such as bow tie， elliptical-core or Panda， which contain at least two different glasses， each one with a different thermal expansion coefficient， the birefringence obtainable with PCFs is highly insensitive to temperature， which is an important feature in many applications. An example of the cross-section of a highly birefringent PCF is reported in Fig. 1.6.
　　Dispersion tailoring
　　The tendency for different light wavelengths to travel at different speeds is a crucial factor in the telecommunication system design. A sequence of short light pulses carries the digitized information. Each of these is formed from a spread of wavelengths and， as a result of chromatic dispersion， it broadens as it travels， thus obscuring the signal. The magnitude of the dispersion changes with the wavelength， passing through zero at 1.3 μm in conventional opticalfibers.
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