21scheme vtu syllabus of visveraya technological university
Photonic crystals.pptx
1. 1
Seminar in Optical Communication Systems
Characteristics of Photonic Crystal
Fibers
Presented by
Lekshmy Sheeja Mohan
2. 2
Contents
• Introduction
• Conventional optical fibers vs Photonic crystal fibers
• Photonic Crystals
• Photonic crystal fibers and its structure
• Index - Guiding PCF
• Hollow Core Fibers
• Fabrication of PCF
• Photonic Crystal Fibers - Properties
• Applications
• Conclusion
• References
3. 3
Introduction
• Initially it is called as holey fibers
• PCF is a new class of optical fiber
• Guiding characteristics - hole diameter ‘d’ and ‘pitch’
• High design flexibility
Fig 2:PCF preform [2]
Fig 1:PCF structure [1]
4. 4
Conventional optical fibers vs Photonic
crystal fibers
• Core - refractive index is higher
• Light propagation -TIR
• Transmission Characteristics
• Dispersion Characteristics
• Bending loss Characteristics
Fig 3 :Conventional optical fiber [3]
• Both core and cladding are made of same
material
• Air holes present in the cladding
• Solid core and hollow core
• M-TIR and Photonic band gap effect
Fig 4 :Photonic Crystal fiber [4]
5. 5
Photonic Crystals
• Refractive index is varying periodically in 3D
(𝑛 = 𝑛 (x,y,z) )
• Photonic band gap - forbid propagation of
certain frequency range of light
• Bragg’s Law - 2asinθ = mλ
• It is an analogous to semiconductor
• 1D - one direction
• 2D - X and Y direction
• 3D - X,Y,Z direction
Fig 5: Photonic crystal [5]
6. 6
Photonic crystal fibers and its structure
• Uses photonic crystals to form the cladding
• Core and cladding – same material
• Size and pitch
• Single mode operation-endlessly single mode
• Dispersion management
• Flexible design
Fig 6: Index guided PCF cross section view [6]
7. 7
Modes of Operation
• Index - Guiding PCF or Solid - Core PCF
• Hollow core fiber or Photonic Bandgap fiber
8. 8
Index - Guiding PCF
• Solid high index core
• Core and cladding is made of same material
• Refractive index of cladding - wavelength ,diameter of the hole and
pitch
• Core – high refractive
• Cladding – low refractive index
• Modified Total Internal Reflection
Fig 7 : Schematic and Microscope picture of a fabricated solid-core
PCF with a triangular lattice of air-holes [7]
9. 9
Hollow Core Fibers
• Hollow air core
• Core - low refractive index
• Cladding - high refractive index
• Photonic band gap effect- propagation
of light over a particular wavelength is forbidden
Fig 8 : Schematic and Microscope picture of a fabricated hollow
core PCF with a triangular lattice of air-holes [7]
10. 10
Hollow Core Fibers – Cont.
• Photonic band gap effect- propagation
of light over a particular wavelength is forbidden
• Light is guided through the core
Fig 9: Reflectivity vs wavelength [8]
11. 11
Fabrication of PCF
• Stack and draw technique
Stacking
Jacking
Drawing
Fig 9 : Fabrication flowchart of PCF
Fig 10 : Schematic of stack-and draw method [9]
12. 12
Photonic Crystal Fibers - Properties
• Endlessly single mode
• Low sensitivity to bend loss
• Hollow core fill with gases or liquid
• Dispersion control and polarization maintaining
14. 14
Conclusion
• Photonic crystal fibers - interest in the scientific area
• Air holes - boosts PCF
• The size and pitch of air holes
- endlessly single-mode guidance
- large mode area
- high numerical aperture, controllable dispersion
• Hollow-core fibers have massive potential
• Higher damage thresholds
15. 15
References
1. Shuguang Li,Xiaoxia Zhang,and Govind P. Agrawal, Characteristics of photonic crystal fibers designed with
an annular core using a single material, 29 April 2013, The Institute of Optics, University of Rochester,New
York 14627, US
2. William Wadsworth, Jonathan Knight and Tim Birks , State-of-the-Art Photonic Crystal Fiber,
https://www.optica-opn.org/home/articles/volume_23/issue_3/features/of-theart_photonic_crystal_fiber/March
2012
3. https://www.newport.com/t/fiber-optic-basics ,Fiber Optic Basics
4. Jonathan Knight, Photonic crystal fibers, 23 February 2007, International Centre for Theoretical Physics,UK
5. Chiappini, A., Tran, L.T.N., Trejo-García, P.M., Zur, L., Lukowiak, A., Ferrari, M. and Righini, G.C., 2020.
Photonic crystal stimuli-responsive chromatic sensors: a short review. Micromachines, 11(3), p.290
6. Dr Abdul Rauf, Photonic Crystal Fiber, National University of Sciences and Technology,March 2014
7. Federica Poli, Annamaria Cucinotta,Stefano Selleri , Photonic Crystal Fibers, Springer Series in Materials
Science (SSMATERIALS, volume 102)
8. Manashee Adhikary, Ravitej Uppu, Cornelis A. M. Harteveld, Experimental probe of a complete 3D photonic
band gap,Vol. 28,pp. 2683-2698(2020)
9. Desmond M. Chow, S. R. Sandoghchi, F. R. Mahamd Adikan , Fabrication of Photonic Crystal Fibers ,
University of Malaya, 3rd International Conference on Photonics 2012, Penang, 1-3 October 2012
