A cylindrical PZT around which some length of a fiber is wound is demonstrated as a component of optical phase shifter and modulator in a single-mode fiber interferometer. Its sensitivity under the operation of DC input mode is 0.18 π rad/V/meter in phase change at the optical wavelength of 6328 . Some characteristics of amplitude response linearity and frequency response uniformity for the AC drive voltage applied to the PZT cylinder are also discussed.

An interferometric method for measuring frequency deviation of semiconductor lasers in wide range of modulation frequencies has been developed. Fringe visibilities of an interfered IM- and FM-modulated light depend on frequency deviation, time delay difference and intensity modulation depth. The applicability of this method has been also discussed.