| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical delay circuit which is miniaturized in comparison to the conventional product and to provide a method of manufacturing the circuit by which the circuits are accurately mass produced. SOLUTION: The optical delay circuit in which an optical waveguide is used is provided with a turning around part 4 in which a core 2 of the optical waveguide turns around in a direction, an input part 5a and an output part 5b, and the depth of the core 2 varies three-dimensionally so that a mutual crossing is avoided. In order to manufacture the optical delay circuit, a method is used by which a prescribed part on an optical waveguide substrate 1 is irradiated with a femtsecond laser light of which the pulse width is 1 ps or shorter and a waveguide is formed by changing the refractive index of the focused point. Further, the accuracy of a delay time of the optical delay circuit is further improved by repeating the irradiation with the femtsecond laser light a plurality of times. COPYRIGHT: (C)2003,JPO |
