Key Technology Of The Spiral-type Integrated Optical Waveguide Delay Line

Phased-array Antenna (PAA) has been used in the area of radar and communication widely since 70's of the 20th century. It is difficult for a conventional PAA to accomplish wide instantaneous bandwidth under wide scan scope because of the restriction of aperture effect and the aperture traverse delay, which affects the system abilities of resolution, detection and imaging of multi-target. However, the implementation of optical true time delay into PAA can obtain wide instantaneous bandwidth under wide scan scope. Optical true time delay technology can take great advantages in respects as time delay fine, reduced bulk and weight, simplification of structure, accommodation to adverse electromagnetic environments, good stability of temperature, etc. Optical time delay technology mostly includes fiber time delay technology and integrated waveguide time delay technology. This paper studies and designs one new type of long bent waveguide time delay line configuration—spiral waveguide configuration.At the beginning, the application background of waveguide time delay line and the development situation of home and abroad have been introduced. This paper establishes the wave equation of bent waveguide from Maxwell equation and studies the single mode transmission condition of three-dimensional ridge waveguide basing on the equation above. Then, the two-dimensional and three-dimensional simulation models respectively have been built up by the finite-difference beam propagation method, discusses the transparent boundary condition and effective index method which will be used in the models. Optical field loss of waveguide is considered mainly in the design of waveguide configuration. This paper focuses on simulating and analyzing the propagation of optical field in the bent waveguide with various radiuses of curvature, the refractive index difference and the cross sections, and obtains the relationship between the different parameters and optical field loss. The dispersion of bent waveguide has been analyzed preliminarily. The main configuration parameters which satisfy the requirement of waveguide delay line design are shown, and the design of configuration of spiral bent waveguide time delay line has been accomplished. At last, several common organic polymer materials and manufacture technologies have been introduced, which provides the manufacture reference of waveguide time delay line.The detailed theory and design have been finished about this new spiral bent waveguide time delay line in this paper, and results of lots of simulations have showed that the performances of this novel spiral bent waveguide are excellent in theory and have established the theoretical foundation for the optical true time delay systems.