Cascaded Mach–Zehnder Architectures for Photonic Integrated Delay Lines

A continuously tunable integrated optical delay line architecture with large bandwidth and bandwidth-delay product is proposed and demonstrated. The non-resonant delay line is based on cascaded Mach-Zehnder interferometers with tunable couplers. The device is operated with a single control signal and outperforms the common ring-resonator-based delay lines in terms of bandwidth-delay product. A device with a delay tuning range of 124 ps is experimentally demonstrated over a transmission bandwidth of 4.5 GHz.