SBS BASED SLOW-LIGHT GENERATION IN PHOTONIC CRYSTAL FIBER

Abstract

In today’s world, the demand of ultra-fast information transfer with ultra-high bandwidths has reached to an extraordinary level. Hence, the transmission in the future internet-backbone will be constrained mostly in the network nodes. Also the power consumption of the network system will increase to indefensible levels. To overcome these constraints power-efficient photonic networks which can provide ultra-fast all-optical switching and routing are necessary. Optical buffering is required for such ultra-fast networks to avoid congestion. Slow-light effect has been investigated as one of the solution of optical buffering. It means slowing down the group velocity of light pulses in a medium. To realize this, many different methods and materials have been developed but due to its significant advantages the nonlinear effect of stimulated Brillouin scattering (SBS) is particularly promising. In this thesis, two different designs of photonic crystal fibers have been proposed for slow-light analysis. The first design is of rectangular core nature with inner air holes having more radius as compared to rest of the air holes. The material used for that design is Tellurite for 100 m long photonic crystal fiber. Another design has been designed with graded index feature i.e. the radius of the air holes keeps on increasing in a regular pattern. The analysis in this fiber has been done for 1 m long photonic crystal fiber with As2Se3 chalcogenide as material of the photonic crystal fiber. Fundamental properties such as confinement loss and effective mode area for both the designs have been simulated. Using those parameters, a maximum time-delay of 154.3 ns has been reported for the first design having tellurite material. The power requirement found to be 26 mW to achieve such high time delay for the length of 100 m long photonic crystal fiber. A Brillouin Gain of 19.07 dB has been reported for that design. For the second design having chalcogenide material, maximum time-delay of 252.8 ns has been reported for 1 m long photonic crystal fiber for a small input pump power of 9.8 mW. The Brillouin Gain achieved for this design was also more as compared to the first design i.e. 99.78 dB. Both the designs were thus compared for slow-light using SBS effect.