Residual dispersion compensation over the S + C + L + U wavelength bands using highly birefringent octagonal photonic crystal fiber

An octagonal photonic crystal fiber (PCF) with an elliptical shape in the center core is numerically investigated for residual dispersion compensation in the wavelength range 1460-1675 nm. The designed fiber exhibits flattened negative dispersion over the S + C + L + U wavelength bands and an average dispersion of -465.5 ps/(nm·km) with an absolute dispersion variation of 10.5 ps/(nm·km). In addition, the proposed PCF shows a high birefringence of 2.68×10(-2) at the operating wavelength 1550 nm, which meets the requirement of high birefringence. Moreover, the variation of two air holes in the first ring up to 5% ensures an average dispersion of -491.5 ps/(nm·km) with a dispersion variation of 13 ps/(nm·km), and birefringence reaches up to 3×10(-2). Furthermore, to evaluate the sensitivity of the fiber dispersion properties, ±5% variation in the optimum parameters is studied.