POLARIZATION INDEPENDENT TYPE OPTICAL WAVELENGTH FILTER, OPTICAL MULTIPLEXING/DEMULTIPLEXING ELEMENT AND MACH-ZEHNDER INTERFEROMETER

摘要

PROBLEM TO BE SOLVED: To provide a polarization independent type optical wavelength filter which uses a multi-mode interference optical waveguide, is made of Si and is easy to create, and then an optical multiplexing/demultiplexing element and a Mach-Zehnder interferometer using the polarization independent type optical wavelength filter.;SOLUTION: The polarization independent type optical wavelength filter is formed by embedding, in a clad 14, the multi-mode interference optical waveguide 16, which is made of single crystal Si, is a rectangular parallelepiped surrounded by first and second side faces 16₁ and 16₂ facing each other, third and fourth side faces 16₃ and 16₄ facing each other and an upper surface and a lower surface 16_u and 16_d facing each other, and wavelength-separates the mixed light of first and second lights of different wavelengths 1.2-1.6 μm independent of polarization, a first optical waveguide 18 which is connected to the first side face and to which the mixed light is input, and second and third optical waveguides 20 and 22, which are connected to the second side face and output the wavelength-separated first and second lights respectively. The refractive index n of the clad is the value of 1-1.6, the thickness t of the multi-mode interference optical waveguide is the value of 0.2-0.4 μm, the width W of the multi-mode interference optical waveguide is the value of 1.0-3.7 μm, and the relation that the width increases as the refractive index of the clad increases and the width increases as the thickness increases is provided.;COPYRIGHT: (C)2011,JPO&INPIT