An all-fiber phase modulator based on lead titanate zirconate coating deposited by dc reactive magnetron sputtering was fabricated and optically characterized. The frequency response showed a flat broadband structure up to 600 kHz, with an efficiency of 0.73 rad/(V m). This is an order of magnitude higher than that for sputtered zinc oxide based phase modulators. Radial mode resonance peaks were observed between 10 and 700 MHz, with a maximum phase modulation amplitude of 0.3 rad at the fundamental radial resonance frequency of 25.6 MHz. (C) 2001 American Institute of Physics.