Determination method, optical control element and manufacturing method thereof

A manufacturing method of an optical control element in the wavelength band, the method comprising:

• a determination method for selecting materials for an optical control element comprising
• determining an operation wavelength band for the optical control element, wherein the optical control element has an optical waveguide formed using an electro-optic material, wherein the operation wavelength band corresponds to wavelengths at which the optical control element is used,
• selecting a formula (I), a formula (II) or both for calculating a figure of merit of the electro-optic material at a wavelength λ based on a required characteristic of the optical control element, wherein the required characteristic of the optical control element includes at least one of a high-speed performance and a power saving, the formula (1) is associated with the high-speed performance and the formula (II) is associated with the power saving,
• calculating a figure of merit FOM1, a figure of merit FOM2 or both using the selecting the selected formula (1), the selected formula (11) or both, wherein the figure of merit FOM1, the figure of merit FOM2, the formula (1) and the formula (11) are represented as:
• FOM
• ⁢
• 1
• =
• n
• 3
• ⁢
• r
• λ
• 2
• (
• I
• )
• FOM
• ⁢
• 2
• =
• n
• 3
• ⁢
• r
• α
• ⁢
• λ
• 2
• (
• II
• )
• wherein n is a refractive index of the electro-optic material, r is an electro-optic coefficient of the electro-optic material, α is a propagation loss per unit length in a phase modulation region in the optical waveguide, and λ is a wavelength equal to, or shorter than 1529 nm,
• in the determining, (i) whether the figure of merit FOM1 at the wavelength λ reaches 1.2 (V-cm)-1 or more, (ii) whether the figure of merit FOM2 at the wavelength λ reaches 0.2 (V-dB)-1 or more, or (iii) whether (i) and (ii) are satisfied, and when (i) is satisfied, the wavelength λ is determined for obtaining the high-speed performance during use of the optical control element, when (ii) is satisfied, the wavelength A is determined for obtaining the saving of power during use of the optical control element;
• when (i) and (ii) are satisfied, the wavelength λ is determined for obtaining both high-speed performance and saving of power during use of the optical control element, and
• selecting the electro-optic material based on the figure of merit FOM1, the figure of merit FOM2 or both;
• and
• forming the optical waveguide using the electro-optic material.