Multi-Stage Mach–Zehnder Based Continuously Tunable Photonic Delay Line

A multi-stage Mach–Zehnder based integrated continuously tunable optical delay line with a large tunability range, increase transmission bandwidth and the vast delay-bandwidth product is demonstrated. The proposed non-resonant delay line is based on cascaded lattice Mach–Zehnder. With the proposed generalized, hitless, and simple control strategy, the delay tunability and delay bandwidth product of the delay line increases with increasing order of Mach–Zehnder based stage. In this paper, we have reported the results of delay line up to order 10 using the proposed control strategy. We have also shown the comparison between single and multiple stage delay lines over various characteristics. We demonstrated that using the proposed control strategy, the four-stage Mach–Zehnder delay line has transmission bandwidth, delay tunability, and delay-bandwidth product that is 12%, 4× , and 10× larger, respectively compared to one-stage Mach–Zehnder delay line. We have also demonstrated that the bandwidth-delay product is almost increasing linearly with an increase in the number of stages of Mach–Zehnder stages.