Research On Integrated Optical Waveguide For Optical True Time Delay Technology

Optical transmission has the greater velocity than electron, and photon not easily affected by electromagnetic interference as the carrier. Therefore, integrated optics has become the inevitable developing trend of information society. With the continuous development of integrated optics, the craftsmanship of integrated optical waveguide is more and more advanced and mature. Compared with the optical delay technology based on fiber, fiber grating or high dispersion fiber, etc, optical delay technology based on silicon waveguide has greater delay accuracy, lower loss, smaller size, lighter weight, and it is easier to integrate with better stability. So optical waveguide delay technical solutions has become a research hotspot in recent years.In this paper, the research provided a detailed theoretical analysis and design basis for optical waveguide delay line. Firstly, this paper introduced the development of optical waveguide materials based-on silicon and optical waveguide delay line. Secondly, this paper analyzed the optical waveguide with the guided wave optical theory, and established two-dimensional and three-dimensional simulation models by using the finite-difference beam propagation method. Thirdly, this paper analyzed the effect of the different structure parameters, cross section size and curvature radius of SOI, SiO2 and Si3N4 waveguide on bending radiation loss in detail with Rsoft and Matlab software, and analyzed the coupling effect of parallel waveguide, designed a low-loss optical waveguide structure.Fourthly, this paper optimized the well-designed SOI, Si3N4 and SiO2 bend waveguide by using bend-simulated method based on the simulation, designed the straight arm type Y-branch and the crank arm type Y-branch. This paper also analyzed the advantages and disadvantages of the three kinds of Y-branch structures.Finally, this paper completed an 1×8 delay line solutions that based on SiO2 channeled waveguide. The width and height of SiO2 channel waveguide are 7 μm, the index difference is 0.36 %. The delay path of optical waveguide by cascading the three crank arm type Y-branch waveguide structures. The size of delay line is 1.3 cm×1.1 cm; the smallest bending radius is 5 mm; the total loss of delay line is 1.88 dB. Each channel has a good loss-consistency, delay difference of adjacent channel is 12.5 ps and the total delay time can be achieved in 0 ~ 87.5 ps.