Abstract: Efficient, simple, miniature and economical piezoelectric and ultrasonic devices employing optical fibers coated with lead-zirconate-titanate (PZT) thin piezoelectric and ferroelectric films are described. The PZT thin films are fabricated chemically by a sol-gel method. Optical fibers can be dipped into the PZT solution, and followed by an annealing and an electric poling process in order to achieve good piezoelectricity in the coated PZT films. This coating process can be devised as an on-line method and thus coating length can be larger than meters. Due to the long coating length, high piezoelectricity, miniature and flexible nature, devices using optical fibers may be used for medical, telecommunication and sensor applications.