Wideband continuously tunable integrated delay line based on cascaded Mach-Zehnder

A novel continuously tunable integrated optical delay line architecture with a record large bandwidth and bandwidth-delay product is proposed and demonstrated. The proposed delay line is based on single and cascaded integrated optical Mach-Zehnder interferometers with tunable couplers. The device can be operated with a single control signal and outperform the common ring-resonator based delay line. Continuously tunable true-time delay from zero to 124 ps is achieved over a bandwidth of 4.5 GHz.