Method of determining quasi-phase matching efficiency in periodically poled structure of optical waveguide, periodically poled structure of optical waveguide, and optical waveguide using the same

An optical waveguide having a periodically poled structure, comprising:

• a core and a cladding for propagating an optical wave;
• and periodic electrodes for inducing a quasi-phase matching, wherein a width w of the periodic electrode is shorter than ½ of a quasi-phase matching period.

A method of determining an quasi-phase matching efficiency in a periodically poled structure of an optical waveguide having periodic electrodes for inducing a quasi-phase matching, the method comprising:

• a step of calculating an electric field applied to the electrodes on the basis of the periodically poled structure, a width of the periodic electrodes, a distance between the electrodes, and a voltage applied to the electrodes;
• and a step of defining a mean distribution of a non-linear optical coefficient contributing to a distribution of a poled electric field from a distribution of the non-linear optical coefficient induced from the calculated electric field, thereby determining the quasi-phase matching efficiency.