Abstract:
Intriguing design of Photonic Crystal Fiber (PCF) with nearly zero dispersion at
operating wavelength with high nonlinear coefficient has been exploited. Several
optical materials including SiO2, GeO2 doped silica and pure Si has been studied for
optimizing a structure for a certain range of operating wavelengths. Design and optical
characteristics of defected GeO2 doped SiO2 square core with regular hexagonal air
hole cladding have been studied extensively. Modal analysis of the proposed
geometries has been performed for a wide range of wavelengths including visible
range (400 -700 nm), short-wavelength infrared band (1.4-3 μm) and mid-wavelength
infrared band (3-8 μm). A good number of defected core structure such as ellipse,
square and some other irregular structures constructed from Bezier curves have also
been investigated to achieve nearly zero dispersion. Achieving smaller effective mode
area is an important feature of our proposed structure. High nonlinear gain can be
mentioned as the eligibility of the proposed fiber as a powerful candidate of Super
Continuum Generation (SCG), Four Wave Mixing (FWM) and Polarization effect of
PCF. In this thesis, different properties of defected GeO2 doped SiO2 square core like
dispersion, effective mode area, nonlinear parameter etc. are investigated
numerically using Full Vector Finite Element method(FEM). Several challenging issues
in the field of nonlinear photonics have been identified which will help also to
optimize an optical waveguide for nonlinear applications from different perspectives.
Description:
We would like to express our sincere gratitude to our thesis supervisor Group Capt. Md.
Afzal Hossain Senior Instructor and Head of the Department, Department of Computer
Science and Engineering (CSE). We would like to express our heartfelt thanks
gratefulness for his instructions, continuous encouragement, valuable discussions and
careful review during the period of this research. His keen sight and wealth of farsighted
advice and supervision have always provided us the precise guiding frameworks of this
research. We have learned many valuable lessons and concepts of the Photonic Crystal
Fiber (PCF) from him, which we have utilized to develop our abilities to work
innovatively and to boost our knowledge. His constant encouragement gave us the
confidence to carry out our work. We would also like to express our profound thanks
and gratitude to all personalities our department of EECE for providing us with all out
support during our thesis work.
Finally of course, we are grateful to our parents for their patience, love and endless
prayers. Without their prayer this work would never have come into existence.
