Optical fiber modulator having an optical fiber having poled portion serving as an electrooptic element and method for making same

摘要

An optical fiber modulator comprises an optical fiber (12), a substrate (10) having a groove pattern (11) in which the optical fiber (12) is fixed, and a modulation unit including a polarizer (18), an electrooptic element, and an analyzer (19) aligned in a light path of the optical fiber in this order, wherein the electrooptic element is made of a poled portion (14) of the optical fiber (12), and when the electrooptic element is in an electric field-free condition, an absolute value, delta , of a phase difference of a beam passed through the electrooptic element is within the following range <MATH> wherein m is an odd number. When the portion (14) of the optical fiber (12) is poled from two different directions, the modulation unit should further include a wave plate, and an absolute value, delta 1, of a phase difference of a beam passed through the wave plate and the electrooptic element is within the following range of (n/2 - 1/6) pi ≤ delta 1≤(n/2 + 1/6) pi wherein n is an odd number. Methods for making the modulators are also described. <IMAGE>