A novel photonic crystal fiber for compression of optical pulses is designed and studied in this paper. The fiber comprises a silica core surrounded by nine rings of air-holes, where air-hole diameter of the innermost ring is gradually reduced along the entire fiber length. In order to obtain the required wavelength dependence of the effective refractive index, finite difference frequency domain method is employed. The calculated chromatic dispersion is flat from 1250 to 1700 nm at the fiber output, and therefore the photonic crystal fiber can be used at a desired wavelength in this range. On the contrary to other studies, chromatic dispersion in this paper is decreasing along the fiber length with the effective mode area. Therefore, during the propagation of solitary waves, the fiber nonlinear parameter increases and consequently the compression ratio is increased. Compression of solitary waves is investigated at the wavelengths of 1250, 1310, 1400, 1550, and 1700 nm. The compression ratio up to 30 for the first-order solitary wave with the length of 1550 nm can be achieved primarily by dispersion varied from 137 to 6 ps·nm-1·km-1 during the wave propagation.