2 results about "Coupling length" patented technology

The application discloses a three-dimensional waveguide cross structure, and relates to the technical field of integrated optics and silicon photonics, and comprises a buried oxygen layer, a first material waveguide layer, a first silicon oxide cover layer, a second material waveguide layer and a second silicon oxide cover layer; the effective coupling length of the projection overlapping area of the first material waveguide layer on the second material waveguide layer satisfies the formula: wherein, L represents the effective coupling length, represents a coupling wavelength, and the value range of n is 1 to 2n, wherein n is an integer, and the constant is less than 1. According to the application, the position of the first material waveguide layer relative to the second material waveguide layer is adjusted, so that the power coupling of the cross port of the three-dimensional waveguide cross structure completes an integer multiple of the coupling period in propagation, thereby reducing the loss and crosstalk caused by coupling enhancement.

The present invention aims to provide a mode conversion device and a design method thereof, which can design arbitrary coupling efficiency and full width at half maximum. The present invention is a mode conversion device having a long-period grating in a core of an optical fiber capable of propagating light in at least two propagation modes, characterized in that the long-period grating satisfies a relationship of mathematical formula C1. Wherein, the full width at half maximum FWHM is a wavelength band in which the coupling efficiency is half compared to the coupling efficiency of the mode conversion of the center wavelength, C is the coupling efficiency, L c is the full coupling length, L g is the grating length, Λ is the grating pitch, and Δβ is the difference in propagation constant of the two propagation modes of the center wavelength as a target of mode conversion; [Mathematical formula C1]