WAVELENGTH CONVERSION ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a wavelength conversion element capable of easily converting the wavelength of an inputted signal light with the same efficiency regardless of the polarization state of the signal light. SOLUTION: This element is provided with an active region 2 having a bulk structure which is provided on a substrate 1 and to which a tensile strain is applied in the direction vertical to the propagation direction of a light and parallel with a lamination direction and in which a gain with respect to a light which has an electric field in the direction vertical to the propagation direction and parallel with the lamination direction is increased so as to become equal to a gain with respect to a light which has an electric field in the direction vertical to the propagation direction and vertical to the lamination direction and a diffraction grating 3 which is adjacent to the active region 2 and has the periodic variation of refractive index in the propagation direction of the light.