Programmable True Time Delay Lines Using Integrated Waveguide Meshes

[EN] We analyze and explore the potential that waveguide-mesh-based architectures used in programmable photonic integrated circuits can be configured to enable true time optical delay lines, which can find applications in different microwave photonics functionalities, such as beamforming and optical filtering. We also propose and experimentally demonstrate an alternative standalone tunable basic unit (TBU) architecture where its internal coupling device is implemented by means of a dual-drive tunable directional coupler (DD-TDC) that performs independent amplitude beam splitting and phase shifting. Compared to the previous alternatives based on 3-dB balanced Mach-Zehnder interferometers, the DD-TDC reduces by more than two times the insertion losses of TBUs enabling the potential realization of larger meshes with a three-fold enhanced step-time resolution. Bandwidth and robustness analysis are also considered.This work was supported in part by the European Research Council under Grant ERC-ADG-2016-471715 UMWP-CHIP, in part by the COST Action CA16220 EUWMP, in part by the Spanish MINECO Projects TEC2014-60378-C2-1-R, and in part by the Gen. Valenciana PROMETEO Project 2017/103.Pérez-López, D.; Sánchez-Gomáriz, E.; Capmany Francoy, J. (2018). Programmable True Time Delay Lines Using Integrated Waveguide Meshes. Journal of Lightwave Technology. 36(19):4591-4601. https://doi.org/10.1109/JLT.2018.283100845914601361