Large Group Delay in Silicon-on-Insulator Chirped Spiral Bragg Grating Waveguide

Limited by large transmission loss, the development of transverse electric (TE) mode silicon-on-insulator (SOI) based on-chip long length chirped grating waveguide faces many difficulties now. To overcome this problem, multi-mode waveguide with a measured transmission loss of 0.7 dB/cm is applied in this paper, and a chirped spiral Bragg grating waveguide (SBGW) is proposed and experimentally demonstrated. The length of the chirped SBGW reaches 2.7 cm, which is the longest SOI based grating reported so far. The total group delay is measured to be 628 ps, with a structure size of only 0.3 mm ² due to the application of spiral configuration. The slope of the linear dispersion is -27.7 ps/nm. This integrated chirped SBGW shows great compatibility with frequently used TE mode SOI devices and has great potential for applications in microwave photonics requiring dispersion control.