| 摘要 |
PURPOSE:To obtain an optical fiber type phase modulator free from the shift of its optical axis, extremely reduced at its insertion loss, capable of low voltage driving, having rapid responsibility, and remarkably reduced at the size of a transmission circuit by arranging an extremely small PLZT chip having a specific shape in a optical fiber in a specific direction. CONSTITUTION:A groove part 4 formed on an optical fiber 1 is a groove forming the shape of a cut part like a shape as shown in the figure by cutting one side of a clad part 2 from its periphery and leaving a part of the other side of the clad part 2 as it is so that the bottom of the groove becomes plane. A rectangular PLZT 5 arranging electrodes 6, 7 on its opposed main surface is engaged with the groove part 4 so that the height (h) in the direction between the electrodes 6, 7 is set up to the vertical direction, the electrode 7 is abutted upon the bottom of the groove part 4 and the thickness (d) direction is set up to the axial direction of a core 3 to constitute the phase modulator of the optical fiber 1 and the PLZT 5 in the groove part 4. The abutting surface of the PLZT 5 upon the core 3 has the area of hXw and constitutes an abutting surface sufficient for covering the whole sectional area of the core 4 and an electric field rectangular to the axial direction of the core 3 is formed.
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