Self-similar pulse compression by defective core photonic crystal fiber with cubic-quintic nonlinearities

We propose a class of photonic crystal fiber called as defective core photonic crystal fiber which can fulfill the self-similar condition for pulse compression in a relatively simple means, without the necessity for a complex approach of changing the size of air holes in the cladding. The proposed model obeys exponential decrease (increase) in dispersion (nonlinearity) along the fiber length and hence compresses the pulse under self-similar technique. We also study the effect of system parameters such as initial dispersion, nonlinearity and chirping in the self-similar compression and compared with adiabatic compression. Using extended nonlinear Schrodinger equation, we have taken into account the effect of quintic nonlinearity on the pulse compression. In the proposed configuration, the quintic nonlinearity shows only a weaker effect in the compression as compared to the cubic nonlinearity. In the present system, we show that the self-similar technique is superior with high degree of compression than the adiabatic route of compressing the pulse. The effect of fiber loss is also taken into account and the critical fiber loss coefficient for compression is estimated.