Compact silicon-based integrated optic time delays

Hybrid multi-mode/single-mode waveguides for low loss

“…However, the high effective index contrast also causes a large of amount of light to scatter from any waveguide roughness, leading to a large propagation loss. Such large propagation losses limit the utility of strip waveguide devices, and in particular make applications that inherently need long propagation paths, such as tunable true time delay [4][5], impossible. One method for lowering such losses is to create much smoother sidewalls by oxidizing silicon strip waveguides [6].…”

Extinction ratio and wavelength flatness for imbalanced Mach–Zehnder interferometer in silicon‐on‐insulator

“…The splitting ratio effects on the imbalanced MZI spectral ER will be addressed and further studied. As the path‐length difference of imbalanced MZI is critical to radio frequency CD and data error rate , the optical low coherence interferometry (OLCI) is utilized to reinforce the delayed optical transmission accuracy . Finally, the spectral ER from the MZDC‐based imbalanced MZI could be illustrated to derive the SOI waveguide propagation loss using the experimental MZDC data on coupling ratios.…”

Polymer waveguide delay device using right‐angle X junctions

“…However, none of these approaches is able to achieve long delay in a small and low‐cost monolithic integrated circuit. Several notable material systems have been used to fabricate waveguide OTTD devices, silica [18], silicon‐on‐insulator [19], and polymers [20]. In comparison of the alternative material systems, the polymer materials have adjustable refractive indices, general higher thermooptical coefficients, and lower thermal conductivities.…”