Spectral narrowing of nearly chirp-free 50-fs pulses delivered by a diode-pumped ytterbium solid-state laser (Yb DPSSL) is experimentally demonstrated using an anomalously dispersive, highly nonlinear photonic-crystal fiber (PCF). The ratio of spectral narrowing and the accompanying temporal pulse broadening are controlled by the peak power of Yb DPSSL pulses at the input of the fiber.